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monit man page on DragonFly

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MONIT(1) User Commands MONIT(1)

NAME
Monit - utility for monitoring services on a Unix system

SYNOPSIS
monit [options] {arguments}

DESCRIPTION
Monit is a utility for managing and monitoring processes, programs,
files, directories and filesystems on a Unix system. Monit conducts
automatic maintenance and repair and can execute meaningful causal
actions in error situations. E.g. Monit can start a process if it does
not run, restart a process if it does not respond and stop a process if
it uses too much resources. You can use Monit to monitor files,
directories and filesystems for changes, such as timestamps changes,
checksum changes or size changes.

Monit is controlled via an easy to configure control file based on a
free-format, token-oriented syntax. Monit logs to syslog or to its own
log file and notifies you about error conditions via customisable alert
messages. Monit can perform various TCP/IP network checks, protocol
checks and can utilise SSL for such checks. Monit provides a HTTP(S)
interface and you may use a browser to access the Monit program.

WHAT TO MONITOR?
You can use Monit to monitor daemon processes or similar programs
running on localhost. Monit is particularly useful for monitoring
daemon processes, such as those started at system boot time. For
instance sendmail, sshd, apache and mysql. In contrast to many other
monitoring systems, Monit can act if an error situation should occur,
e.g.; if sendmail is not running, monit can start sendmail again
automatically or if apache is using too many resources (e.g. if a DoS
attack is in progress) Monit can stop or restart apache and send you an
alert message. Monit can also monitor process characteristics, such as
how much memory or cpu cycles a process is using.

You can also use Monit to monitor files, directories and filesystems on
localhost. Monit can monitor these items for changes, such as
timestamps changes, checksum changes or size changes. This is also
useful for security reasons - you can monitor the md5 or sha1 checksum
of files that should not change and get an alert or perform an action
if they should change.

Monit can monitor network connections to various servers, either on
localhost or on remote hosts. TCP, UDP and Unix Domain Sockets are
supported. Network test can be performed on a protocol level; Monit has
built-in tests for the main Internet protocols, such as HTTP, SMTP etc.
Even if a protocol is not supported you can still test the server
because you can configure Monit to send any data and test the response
from the server.

Monit can be used to test programs or scripts at certain times, much
like cron, but in addition, you can test the exit value of a program
and perform an action or send an alert if the exit value indicates an
error. This means that you can use Monit to perform any type of check
you can write a script for.

Finally, Monit can be used to monitor general system resources on
localhost such as overall CPU usage, Memory and System Load.

GENERAL OPERATION
The behaviour of Monit is controlled by command-line options and a run
control file, monitrc, the syntax of which we describe in a later
section. Command-line options override .monitrc declarations.

The default location for monitrc is ~/.monitrc. If this file does not
exist, Monit will try /etc/monitrc and a few other places. See FILES
for details. You can also specify the control file directly by using
the -c command-line switch to monit. For instance,

$ monit -c /var/monit/monitrc

Before Monit is started the first time, you can test the control file
for syntax errors:

$ monit -t
$ Control file syntax OK

If there was an error, Monit will print an error message to the
console, including the line number in the control file from where the
error was found.

Once you have a working Monit control file, simply start Monit from the
console, like so:

$ monit

You can change some configuration directives via command-line switches,
but for simplicity it is recommended that you put these in the control
file.

Monit will detach from the terminal and run as a background process,
i.e. as a daemon process. As a daemon, Monit runs in cycles; It monitor
services, then goes to sleep for a configured period, then wakes up and
start monitoring again in an endless loop.

Options
The following options are recognized by Monit. However, it is
recommended that you set options (when applicable) directly in the
.monitrc control file.

-c file
Use this control file

-d n
Run Monit as a daemon once per n seconds. Or use "set
daemon" in monitrc.

-g name
Set group name for start, stop, restart, monitor, unmonitor,
status and summary action.

-l logfile
Print log information to this file. Or use "set logfile"
in monitrc.

-p pidfile
Use this lock file in daemon mode. Or use "set pidfile"
in monitrc.

-s statefile
Write state information to this file. Or use "set
statefile" in monitrc.

-I
Do not run in background (needed for run from init)

-i
Print Monit's unique ID

-r
Reset Monit's unique ID. Use with caution

-t
Run syntax check for the control file

-v
Verbose mode, work noisy (diagnostic output)

-vv
Very verbose mode, same as -v plus log stack-trace on error

-H [filename]
Print MD5 and SHA1 hashes of the file or of stdin if the
filename is omitted; Monit will exit afterwards

-V
Print version number and patch level

-h
Print a help text

Arguments
Once you have Monit running as a daemon process, you can call Monit
with one of the following arguments. Monit will then connect to the
Monit daemon (on TCP port 127.0.0.1:2812 by default) and ask the Monit
daemon to perform the requested action. In other words; calling monit
without arguments starts the Monit daemon, and calling monit with
arguments enables you to communicate with the Monit daemon process.

start all
Start all services listed in the control file and enable monitoring
for them. If the group option is set (-g), only start and enable
monitoring of services in the named group ("all" is not required in
this case).

start name
Start the named service and enable monitoring for it. The name is a
service entry name from the monitrc file.

stop all
Stop all services listed in the control file and disable their
monitoring. If the group option is set, only stop and disable
monitoring of the services in the named group ("all" is not
required in this case).

stop name
Stop the named service and disable its monitoring. The name is a
service entry name from the monitrc file.

restart all
Stop and start all services. If the group option is set, only
restart the services in the named group ("all" is not required in
this case).

restart name
Restart the named service. The name is a service entry name from
the monitrc file.

monitor all
Enable monitoring of all services listed in the control file. If
the group option is set, only start monitoring of services in the
named group ("all" is not required in this case).

monitor name
Enable monitoring of the named service. The name is a service entry
name from the monitrc file. Monit will also enable monitoring of
all services this service depends on.

unmonitor all
Disable monitoring of all services listed in the control file. If
the group option is set, only disable monitoring of services in the
named group ("all" is not required in this case).

unmonitor name
Disable monitoring of the named service. The name is a service
entry name from the monitrc file. Monit will also disable
monitoring of all services that depends on this service.

status [name]
Print service status information.

summary [name]
Print a short status summary.

reload
Reinitialise a running Monit daemon, the daemon will reread its
configuration, close and reopen log files.

quit
Kill the Monit daemon process

validate
Check all services listed in the control file. This action is also
the default behaviour when Monit runs in daemon mode.

procmatch regex
Allows for easy testing of pattern for process match check. The
command takes regular expression as an argument and displays all
running processes matching the pattern.

THE MONIT CONTROL FILE
Monit is configured and controlled via a control file called monitrc.
The default location for this file is ~/.monitrc. If this file does not
exist, Monit will try /etc/monitrc, then @sysconfdir@/monitrc and
finally ./monitrc. If you build Monit from source, the value of
@sysconfdir@ can be given at configure time as ./configure
--sysconfdir. For instance, using ./configure --sysconfdir
/var/monit/etc will make Monit search for monitrc in /var/monit/etc

To protect the security of your control file and passwords the control
file must have read-write permissions no more than 0700 (u=xrw,g=,o=);
Monit will complain and exit otherwise.

When there is a conflict between the command-line arguments and the
arguments in this file, the command-line arguments takes precedence.

Monit uses its own Domain Specific Language (DSL); The control file
consists of a series of service entries and global option statements.

Comments begin with a '#' and extend through the end of the line.
Otherwise the file consists of a series of service entries or global
option statements in a free-format, token-oriented syntax.

You can use noise keywords like 'if', 'and', 'with(in)', 'has',
'us(ing|e)', 'on(ly)', 'then', 'for', 'of' anywhere in an entry to make
it resemble English. They're ignored, but can make entries much easier
to read at a glance. Keywords are case insensitive.

There are three kinds of tokens: grammar, numbers (i.e. decimal digit
sequences) and strings. Strings can be either quoted or unquoted. A
quoted string is bounded by double quotes and may contain whitespace
(and quoted digits are treated as a string). An unquoted string is any
whitespace-delimited token, containing characters and/or numbers.

On a semantic level, the control file consists of three types of
entries:

1. Global set-statements
A global set-statement starts with the keyword "set" and the item
to configure.

2. Global include-statement
The include statement consists of the keyword "include" and a glob
string. This statement is used to include configure directives from
separate files.

3. One or more service entry statements.
Each service entry consists of the keywords "check", followed by
the service type. Each entry requires a unique descriptive name,
which may be freely chosen. This name is used by Monit to refer to
the service internally and in all interactions with the user.

Currently, nine types of check statements are supported:

1. CHECK PROCESS <unique name> <PIDFILE <path> | MATCHING <regex>>
<path> is the absolute path to the program's pid-file. A pid-file
is a file, containing a Process's unique ID. If the pid-file does
not exist or does not contain the PID number of a running process,
Monit will call the entry's start method if defined.

<regex> is an alternative to using PID files and uses process name
pattern matching to find the process to monitor. The first match is
used so this form of check is most useful if the process name is
unique. Pid-file should be used where possible as it defines
expected pid exactly (pattern matching won't be useful for
processes which start a child process using fork/clone as the child
will match the same pattern temporarily). You can test if a process
match a pattern from the command-line using "monit procmatch
"regex-pattern"". This will lists all processes matching or not,
the regex-pattern.

2. CHECK FILE <unique name> PATH <path>
<path> is the absolute path to the file. If the file does not
exist, Monit will call the entry's start method if defined, if
<path> does not point to a regular file type (for instance a
directory), Monit will disable monitoring of this entry. If Monit
runs in passive mode or the start method is not defined, Monit will
just send an alert on error.

3. CHECK FIFO <unique name> PATH <path>
<path> is the absolute path to the fifo. If the fifo does not
exist, Monit will call the entry's start method if defined, if
<path> does not point to a fifo type (for instance a directory),
Monit will disable monitoring of this entry. If Monit runs in
passive mode or the start method is not defined, Monit will just
send an alert on error.

4. CHECK FILESYSTEM <unique name> PATH <path>
<path> is the path to the device/disk, mount point, file or a
directory which is part of a filesystem. It is recommended to use a
block special file directly (for example /dev/hda1 on Linux or
/dev/dsk/c0t0d0s1 on Solaris, etc.) If you use a mount point (for
example /data), note if the filesystem is unmounted the test will
still be true because the mount point exist.

If the filesystem becomes unavailable, Monit will call the entry's
start method if defined. if <path> does not point to a filesystem,
Monit will disable monitoring of this entry. If Monit runs in
passive mode or the start method is not defined, Monit will just
send an alert on error.

5. CHECK DIRECTORY <unique name> PATH <path>
<path> is the absolute path to the directory. If the directory does
not exist, Monit will call the entry's start method if defined. If
<path> does not point to a directory, monit will disable monitoring
of this entry. If Monit runs in passive mode or the start methods
is not defined, Monit will just send an alert on error.

6. CHECK HOST <unique name> ADDRESS <host address>
The host address can be specified as a hostname string or as an IP-
address string on a dotted decimal format. Such as, tildeslash.com
or "64.87.72.95".

7. CHECK SYSTEM <unique name>
The unique name is usually the local host name, but any descriptive
name can be used. If you use the variable $HOST as the name, it
will expand to the hostname. This check allows one to monitor
general system resources such as CPU usage, total memory usage or
load average. The unique name is used as the system hostname in
mail alerts and as the initial name of the host entry in M/Monit.

8. CHECK PROGRAM <unique name> PATH <executable file> [TIMEOUT <number>
SECONDS]
<path> is the absolute path to the executable program or script.
The status test allows one to check the program's exit status. If
the program does not finish executing within <number> seconds,
Monit will terminate it. The default program timeout is 300 seconds
(5 minutes). The output of the program is recorded and made
available in the User Interface and in alerts (up to 1kB).

9. CHECK NETWORK <unique name> <ADDRESS <ipaddress> | INTERFACE <name>>
<ipaddress> is the IPv4 or IPv6 address of the monitored network
interface. It is also possible to use interface name, such as
"eth0" on Linux.

LOGGING
Monit will log status and error messages to a log file. Use the set
logfile statement in the monitrc control file. To setup Monit to log to
its own logfile, use e.g. set logfile /var/log/monit.log. If syslog is
given as a value for the "-l" command-line switch (or the keyword set
logfile syslog is found in the control file) Monit will use the syslog
system daemon to log messages with a priority assigned to each message
based on the context. To turn off logging, simply do not set the
logfile in the control file (and of course, do not use the -l switch)

The format for logfile is:

[date] priority : message

for example:

[CET Jan 5 18:49:29] info : 'mymachine' Monit started

DAEMON MODE
Use

set daemon n (where n is a number in seconds)

to specify Monit's poll cycle length and run Monit in daemon mode. You
must specify a numeric argument which is a polling interval in seconds.
In daemon mode, Monit detaches from the console, puts itself in the
background and runs continuously, monitoring each specified service and
then goes to sleep for the given poll interval, wakes up and start
monitoring again in an endless cycle.

Alternatively, you can use the "-d" command line switch to set the poll
interval, but it is strongly recommended to set the poll interval in
your ~/.monitrc file, by using set daemon.

Monit will then always start in daemon mode. If you do not use this
statement and do not start monit with the -d option, Monit will just
run through the service checks once and then exit. This might be useful
in some situations, but Monit is primarily designed to run as a daemon
process.

Calling "monit" with a Monit daemon running in the background sends a
wake-up signal to the daemon, forcing it to check services immediately.
Calling "monit" with the quit argument will kill a running Monit daemon
process instead of waking it up.

INIT SUPPORT
The "set init" statement prevents Monit from transforming itself into a
daemon process. Instead Monit will run as a foreground process. (You
should still use "set daemon" to specify the poll cycle).

This is required to run Monit from init. Using init to start Monit is
probably the best way to run Monit if you want to be certain that you
always have a running Monit daemon on your system. Another option is to
run Monit from crontab. In any case, you should make sure that the
control file does not have any syntax errors before you start Monit
from init or crontab (use "monit -t" to check).

To setup Monit to run from init, you can either use the "set init"
statement in Monit's control file or use the "-I" option from the
command line. Here is what you must add to "/etc/inittab":

# Run Monit in standard run-levels
mo:2345:respawn:/usr/local/bin/monit -Ic /etc/monitrc

After you have modified init's configuration file, you can run the
following command to re-examine /etc/inittab and start Monit:

telinit q

For systems without telinit:

kill -1 1

If Monit is used to monitor services that are also started at boot time
(e.g. services started via SYSV init rc scripts or via inittab) then,
in some cases, a race condition could occur. That is; if a service is
slow to start, Monit can assume that the service is not running and
possibly try to start it and raise an alert, while, in fact the service
is already about to start or already in its startup sequence. Please
see the FAQ for a solution to this problem. The short version is to
start Monit on a higher run-level after system processes.

INCLUDE FILES
The Monit control file, "monitrc", can include additional configuration
files. This feature helps one to organise configuration into separate
files instead of having everything in one file, if you like this kind
of thing. Include statements can be placed at virtually any place in
"monitrc" though the convention is at the bottom. The syntax is the
following:

include globstring

The globstring is any kind of string as defined in glob(7). Thus, you
can refer to a single file or you can load several files at once. If
you want to use whitespace in your string the globstring needs to be
embedded into quotes (') or double quotes ("). If the globstring
matches a directory instead of a file, it is silently ignored.

Any include statements in an included file are parsed as in the main
control file.

If the globstring matches several results, the files are included in a
non sorted manner. If you need to rely on a certain order, you should
avoid wild-card globbing and instead specify the full path of files
included.

An example,

include /etc/monit.d/*.cfg

This will load any file matching the globstring. That is, all files in
/etc/monit.d that ends with the prefix .cfg.

SSL OPTIONS
Common SSL/TLS options can be set using the following statement and
will apply to all SSL connections made through Monit:

SET <SSL | TLS> [OPTIONS] {
VERSION: <AUTO | SSLV2 | SSLV3 | TLSV1 | TLSV11 | TLSV12>
VERIFY: <ENABLE | DISABLE>
SELFSIGNED: <ALLOW | REJECT>
CLIENTPEMFILE: <path>
CACERTIFICATEFILE: <path>
CACERTIFICATEPATH: <path>
}

VERSION set the specific SSL/TLS version to use. By default Monit uses
AUTO. In AUTO mode, only TLS is used, SSLv2 and SSLv3 is considered
obsolete. If you have to use SSLv2 or SSLv3, you must explicitly set
the version.

VERIFY enable SSL server certificate verification. This will verify and
report an error if the server certificate is not trusted, not valid or
has expired. By default certificate verification is disabled, though we
recommend enabling it, otherwise there is no guarantee that Monit
speaks with the server you think it speaks with.

SELFSIGNED self-signed certificates are rejected by default. Use this
option to allow self-signed certificates.

CLIENTPEMFILE set the path to the SSL client certificate "database-
file" in PEM format. If an SSL server requires client certificate
authentication, Monit will try to find a public key certificate in this
file which match the server's Certificate Authority and if found, use
this certificate for client authentication.

CACERTIFICATEFILE set the path to the PEM encoded file containing
Certificate Authority (CA) certificates. Monit uses OpenSSL's default
CA cartificates if this options is not used (you can use "openssl
version -d" command to get the default CA certificates). Many
distributions comes with SSL and CA certificates already setup and
using this option is normally not necessary.

CACERTIFICATEPATH set the path to the directory containing Certificate
Authority (CA) certificates. Monit uses OpenSSL's default CA
certificates if this options is not used (you can use "openssl version
-d" command to get the default CA certificates). Many distributions
comes with SSL and CA certificates already setup and using this option
is normally not necessary.

The SSL options statement can be used both globally (default for all
SSL/TLS connection made through Monit) or local in a check, in
mailserver settings or with the mmonit statement, and will then
override or extend the global settings.

To set global SSL options, put this statement near the top of your
.monitrc file:

set ssl options {...}

Here is an example of setting both global and local SSL options:

# Enable certificate verification for all SSL connections
# Self-signed certificates are not allowed by default
set ssl options {
verify: enable
}

# Verify certificate (via global setting)
# Allow self-signed certificate for this check
check host example with address example.com
if failed
port 443
protocol https
with ssl options {selfsigned: allow}
then alert

# Do not verify example2.com's certificate (override global setting)
check host example2 with address example2.com
if failed
port 443
protocol https
with ssl options {verify: disable}
then alert

MONIT HTTPD
If specified in the control file, Monit will start with HTTP support.
You can then use Monit CLI to start and stop services, disable or
enable service monitoring as well as view the status of each service.

If HTTP support is enabled over TCP rather than over a Unix Socket, you
can also view Monit's informative dashboard in your web browser.

Note that if HTTP support is disabled, the Monit CLI interface will
have reduced functionality, as most CLI commands (such as "monit
status") need to communicate with the Monit background process via the
HTTP interface. We strongly recommend having HTTP support enabled. If
security is a concern, bind the HTTP interface to local host only or
use Unix Socket so Monit is not accessible from the outside.

Syntax for TCP port:

Example:

set httpd port 2812
allow username:password

You can now use <http://localhost:2812/> to access Monit's web
interface from a browser, after you have entered username and password
as credentials.

Syntax for Unix Socket:

SET HTTPD UNIXSOCKET <path>
ALLOW <user:password>+

Example:

set httpd unixsocket /var/run/monit.sock
allow username:password

Options:

UNIXSOCKET set the path to the Unix Socket Monit should bind to and
listen on.

PORT set the port Monit should bind to and listen on. Monit is usually
setup on port 2812.

ADDRESS make Monit listen on a specific interface only. For example if
you don't want to expose Monit's web interface to the network, bind it
to localhost only. Monit will accept connections on any address by
default (if ADDRESS option is missing).

For example to limit the web interface to localhost only:

set httpd
port 2812
use address 127.0.0.1
allow username:password

SSL enable TLS for Monit's web interface. The PEMFILE option holds both
the server's private key and certificate. This file should be stored in
a safe place on the filesystem and should have strict permissions, no
more than 0700.

For example:

set httpd
port 2812
ssl enable
pemfile /etc/certs/monit.pem
allow myuser:mypassword

You can now use <https://localhost:2812/> to access the Monit web
server over a TLS encrypted connection.

OpenSSL FIPS is supported. To enable FIPS mode (provided your OpenSSL
library supports it), add this statement to Monit control file:

SET FIPS

CLIENTPEMFILE client certificate based authentication. A connecting
client has to provide a certificate known to Monit in order to connect.
This file also needs to have all necessary CA certificates. By default
self-signed client certificates are not allowed. If you want to use a
self signed certificate from a client it has to be allowed explicitly
with the ALLOWSELFCERTIFICATION statement.

For example:

set httpd
port 2812
ssl enable
pemfile /etc/certs/monit.pem
clientpemfile /etc/certs/monit-client.pem

SIGNATURE can be used to hide Monit version from the HTTP response
header and error pages. For example:

set httpd
port 2812
signature disable
allow myuser:mypassword

Authentication
Access to the Monit web interface is controlled primarily via the ALLOW
option which is used to specify authentication and authorise only
specific clients to connect.

If the Monit command line interface is being used, at least one
cleartext password is necessary (see bellow), otherwise the Monit
command line interface will not be able to connect to the Monit web
interface.

Clients trying to connect to Monit, but submit a wrong username and/or
password are logged with their IP-address.

Client certificates

This authentication method is a strong authentication mechanism and
employ HTTPS client certificates to verify the authenticity of a
connecting client. Clients must posses a Public Key Certificate known
by Monit. The client must connect to Monit over SSL and Monit ask the
client to send its certificate. Upon receiving the certificate Monit
compares the certificate to certificates located in the CLIENTPEMFILE
file. Access is granted if the client certificate is in this file. See
CLIENTPEMFILE above for details.

Host and network allow list

Monit maintains an access-control list of hosts and networks allowed to
connect. You can add as many hosts as you want to, but only hosts with
a valid domain name or its IP address are allowed.

Monit will query a name server to check any hosts trying to connect. If
a host (client) is trying to connect, but cannot be found in the access
list or cannot be resolved, Monit will shutdown the connection to the
client promptly.

Control file example:

set httpd port 2812
allow localhost
allow my.other.work.machine.com
allow 10.1.1.1
allow 192.168.1.0/255.255.255.0
allow 10.0.0.0/8

Clients, not mentioned in the allow list, trying to connect to Monit
will be denied access and are logged with their IP-address.

Basic Authentication

Monit supports Basic Authentication as described in RFC 2617.

In short; a server challenge a client (e.g. a Browser) to send
authentication information (username and password) and if accepted, the
server will allow the client access to the requested document.

The biggest weakness with Basic Authentication is that username and
password is sent in clear-text over the network (i.e. base64 encoded).
It is therefor recommended that you do not use this authentication
method unless you run Monit with ssl support. With ssl, it is safe to
use Basic Authentication since all HTTP data, including Basic
Authentication headers will be encrypted.

Cleartext user and password

Monit will use Basic Authentication if an allow statement contains a
username and a password separated with a single ':' character. Special
characters can be used, but for non-alphanumerics the password has to
be quoted.

Syntax:

ALLOW <username>:<password>

PAM

PAM is supported on platforms which provide PAM (such as Linux, Mac OS
X, FreeBSD, NetBSD).

Syntax:

ALLOW @<group>

where "group" is the group name allowed to access Monit's web
interface. Monit uses a PAM service called monit for PAM
authentication, see the PAM manual page for detailed instructions on
how to set the PAM service and PAM authentication plugins.

Sample PAM service for Monit on Mac OS X (store as "/etc/pam.d/monit"
file):

# monit: auth account password session
auth sufficient pam_securityserver.so
auth sufficient pam_unix.so
auth required pam_deny.so
account required pam_permit.so

And monitrc config which only allows group "admin" authenticated via
PAM to access the web interface:

set httpd
port 2812
allow @admin

htpasswd file

Alternatively you can use files in "htpasswd" format (one user:passwd
entry per line), like so: allow [cleartext|crypt|md5] /path [users]. By
default cleartext passwords are read. In case the passwords are
digested it is necessary to specify the cryptographic method. If you do
not want all users in the password file to have access to Monit you can
specify only those users that should have access, in the allow
statement. Otherwise all users are added.

Example1:

set httpd port 2812
allow hauk:password
allow md5 /etc/httpd/htpasswd john paul ringo george

If you use this method together with a host list, then only clients
from the listed hosts will be allowed to connect to the Monit HTTP
server and each client will be asked to provide a username and a
password.

Example2:

set httpd port 2812
allow localhost
allow 10.1.1.1
allow hauk:"passw@rd"

If you only want to use Basic Authentication, then just provide allow
entries with username and password or password files as in example 1
above.

Read-only users

Finally it is possible to define some users as read-only. A read-only
user can read the Monit web pages but will not get access to push-
buttons and cannot change a service from the web interface.

set httpd port 2812
allow admin:password
allow hauk:password read-only
allow @admins
allow @users read-only

A user is set to read-only by using the read-only keyword after
username:password. In the above example the user hauk is defined as a
read-only user, while the admin user has all access rights.

ALERT MESSAGES
Monit will raise an alert in the following situations:

o A service does not exist (e.g. process is not running)
o Cannot read service data (e.g. cannot get filesystem usage)
o Execution of a service related script failed (e.g. start failed)
o Invalid service type (e.g. if path points to directory instead of file)
o Custom test script returned error
o Ping test failed
o TCP/UDP connection and/or port test failed
o Resource usage test failed (e.g. cpu usage too high)
o Checksum mismatch or change (e.g. file changed)
o File size test failed (e.g. file too large)
o Timestamp test failed (e.g. file is older then expected)
o Permission test failed (e.g. file mode doesn't match)
o An UID test failed (e.g. file owned by different user)
o A GID test failed (e.g. file owned by different group)
o A process' PID changed out of Monit's control
o A process' PPID changed out of Monit control
o Too many service recovery attempts failed
o A file content test found a match
o Filesystem flags changed
o A service action was performed by administrator
o A network link failed
o A network link capacity changed
o A network link saturation failed
o A network link upload/download rate failed
o Monit was started, stopped or reloaded

To get an alert via e-mail, set the alert target using the global "set
alert" statement (for all services) or the "alert" statement in the
context of a service entry (for a single service).

Setting an alert recipient
If an event occurs, Monit will send an alert. There are two kinds of
alert statement: global and local.

Global syntax:

SET ALERT mail-address [[NOT] {event, ...}] [REMINDER cycles]

Example:

set alert foo@bar

will send a default email to the address foo@bar whenever any event
occurs on any service.

If you want to send alert messages to more email addresses, add a "set
alert 'email'" statement for each address.

It is also possible to use the local alert statement in the context of
a service check to enable alert for the given service only:

ALERT mail-address [[NOT] {event, ...}] [REMINDER cycles]

Local alert example:

check host myhost with address 1.2.3.4
if failed port 3306 protocol mysql then alert
if failed port 80 protocol http then alert
alert foo@baz # Local service alert

You can combine global and local alert statements. If there is a
conflict, the local alert has precedence and overrides the global
statement.

Setting an event filter

If you only want an alert message sent for certain events, list them in
an "{event, ...}" block, e.g.:

set alert foo@bar only on { timeout, nonexist }

The event list can also be negated to send alerts for all events except
those which are listed, by prepending the list with the word "not". For
example, to receive all alerts except notification about Monit program
start and stop:

set alert foo@bar but not on { instance }

Here is a list of all possible event types emitted by Monit. Values
from the first column can be used in the event filter list mentioned
above:

Each alert recipient can have it's own filter, for example:

set alert foo@bar { nonexist, timeout, resource, icmp, connection }
set alert security@bar on { checksum, permission, uid, gid }
set alert admin@bar

Setting an error reminder

Monit by default sends just one notification if a service failed and
another when/if it recovers. If you want to be notified that the
service is still in a failed state, you can use the reminder option in
the alert statement:

SET ALERT mail-address [WITH] REMINDER [ON] number [CYCLES]

For example if you want to be notified each tenth cycle if a service
remains in a failed state, you can use:

alert foo@bar with reminder on 10 cycles

Likewise if you want to be notified on each failed cycle, you can use:

alert foo@bar with reminder on 1 cycle

Disabling alerts for some service
To suppress alerts for some user and service, add the "noalert"
statement in the context of a service check.

NOALERT mail-address

Example (send all alerts to foo@bar except for service p3):

set alert foo@bar

check process p1 with pidfile /var/run/p1.pid

check process p2 with pidfile /var/run/p2.pid

check process p3 with pidfile /var/run/p3.pid
noalert foo@bar

Message format
The alert message format can be modified by using the "set mail-format"
statement:

SET MAIL-FORMAT {mail-format}

Example:

set mail-format {
from: monit@foo.bar
reply-to: support@domain.com
subject: $SERVICE $EVENT at $DATE
message: Monit $ACTION $SERVICE at $DATE on $HOST: $DESCRIPTION.
Yours sincerely,
monit
}

The from: option is the sender's email address. That is, the email
address Monit will pretend it is sending alerts from. It does not have
to be a real email-address only a proper formatted address.

The reply-to: option can be used to set the reply-to mail header.

The subject: option sets the message subject and must be on only one
line.

The message: option sets the mail body. This option should always be
the last in a mail-format statement. The mail body can be as long as
needed, but must not contain the block-closing '}' character.

You need not use all options, only the option which you want to
override. For example to globally change the senders address only:

set mail-format { from: bofh@foo.bar }

The subject and body may contain $NAME variables, which are expanded by
Monit. Here is a list of variables that can be used when composing an
alert message.

· $EVENT

A string describing the event that occurred.

· $SERVICE

The service name

· $DATE

The current time and date (RFC 822 date style).

· $HOST

The name of the host Monit is running on

· $ACTION

The name of the action which was done by Monit.

· $DESCRIPTION

The description of the error condition

Setting a mail server for alert delivery
The mail server Monit should use to send alert messages is defined with
a "set mailserver" statement:

SET MAILSERVER
<hostname|ip-address>
[PORT number]
[USERNAME string] [PASSWORD string]
[using SSL [with options {...}]
[CERTIFICATE CHECKSUM [MD5|SHA1] <hash>],
...
[with TIMEOUT X SECONDS]
[using HOSTNAME hostname]

Multiple mail servers can be set by using a comma separated list. If
Monit cannot connect to the first server, it will try the next in the
list and so on.

The port statement allows to override the default SMTP port (465 for
SSL, or 25 for TLS and non secure connection).

Monit supports AUTH PLAIN and AUTH LOGIN for SMTP authentication. You
can set a username and a password using the USERNAME and PASSWORD
options.

You can set SSL/TLS options for the connection and also check a SSL
certificate checksum.

The default connection timeout is 5 seconds. You can rise this limit
using the TIMEOUT option.

Example (setting two mail servers for failover):

set mailserver smtp.gmail.com, smtp.other.host

By default, Monit uses the local host name in SMTP HELO/EHLO and in the
Message-ID header. You can override this using the HOSTNAME option.

Event queue
If no mail server is available, Monit can queue events in the local
file-system for retry until the mail server recovers.

If Monit is used with M/Monit, the event queue provides a safe event
store for M/Monit in the case of temporary problems.

The event queue is persistent across Monit restarts and provided that
the back-end filesystem is persistent, across system restart as well.

By default, the queue is disabled and if the alert handler fails, Monit
will simply drop the alert message.

To enable the event queue, add the following statement:

SET EVENTQUEUE BASEDIR <path> [SLOTS <number>]

The <path> is the path to the directory where events will be stored.

Optionally if you want to limit the queue size, use the slots option to
only store up to number event messages.

Example:

set eventqueue basedir /var/monit slots 5000

If you are running more then one Monit instance on the same machine,
you must use separated event queue directories.

SERVICE METHODS
Each service can have associated start, stop and restart methods which
Monit can use to execute action on the service.

Syntax:

<START | STOP | RESTART> [PROGRAM] = "program"
[[AS] UID <number | string>]
[[AS] GID <number | string>]
[[WITH] TIMEOUT <number> SECOND(S)]

If the "program" is a shell script it must begin with "#!" and the
remainder of the first line must specify an interpreter for the
program. e.g. "#!/bin/sh"

The "program" must also be executable (for example mode 0755).

It's possible to write scripts directly into the program this way:

stop = "/bin/bash -c 'kill -s SIGTERM `cat /var/run/process.pid`'"

By default the program is executed as the user under which Monit is
running. If Monit is running as root, you may optionally specify the
UID and GID the executed program should switch to.

Example:

check process mmonit with pidfile /usr/local/mmonit/mmonit/logs/mmonit.pid
start program = "/usr/local/mmonit/bin/mmonit" as uid "mmonit" and gid "mmonit"
stop program = "/usr/local/mmonit/bin/mmonit stop" as uid "mmonit" and gid "mmonit"

In the case of a process check, Monit will wait up to 30 seconds for
the start/stop action to finish before giving up and report an error.
You can override this timeout using the TIMEOUT option.

Example:

check process foobar with pidfile /var/run/foobar.pid
start program = "/etc/init.d/foobar start" with timeout 60 seconds
stop program = "/etc/init.d/foobar stop"

SERVICE POLL TIME
Services are checked in regular intervals by the "set daemon n"
statement. Checks are performed in the same order as they are written
in the ".monitrc" file, except if dependencies are setup between
services, where pre-requisite services are tested first.

It is possible to modify a service check schedule by using the "every"
statement.

There are three variants:

1. custom interval based on a poll cycle multiple
EVERY [number] CYCLES

2. check is schedule based on a cron-style string
EVERY [cron]

3. do-not-check schedule based on a cron-style string
NOT EVERY [cron]

A cron-style string, consist of 5 fields separated with white-space.
All fields are required:

The special characters:

Character: | Description:
---------------------------------------------------------------
* (asterisk) | The asterisk indicates that the expression will
| match for all values of the field; e.g., using
| an asterisk in the 4th field (month) would
| indicate every month.
- (hyphen) | Hyphens are used to define ranges. For example,
| 8-9 in the hour field indicate between 8AM and
| 9AM. Note that range is from start time until and
| including end time. That is, from 8AM and until
| 10AM unless minutes are set. Another example,
| 1-5 in the weekday field, specify from monday to
| friday (including friday).
, (comma) | Comma are used to specify a sequence. For example
| 17,18 in the day field indicate the 17th and 18th
| day of the month. A sequence can also include
| ranges. For example, using 1-5,0 in the weekday
| field indicate monday to friday and sunday.

Example 1: Check once per two cycles

check process nginx with pidfile /var/run/nginx.pid
every 2 cycles

Example 2: Check every workday 8AM-7PM

check program checkOracleDatabase
with path /var/monit/programs/checkoracle.pl
every "* 8-19 * * 1-5"

Example 3: Do not run the check in the backup window on Sunday 0AM-3AM

check process mysqld with pidfile /var/run/mysqld.pid
not every "* 0-3 * * 0"

Limitations:

The current scheduler is poll cycle based. When a service check is
constraint with the every cron statement, Monit will check whether the
current time match the cron-string pattern. If it does, the check is
performed, otherwise it is skipped. The cron specification thus does
not guarantee when exactly the test will run, this depends on the
default poll time and the length of the check cycle. In other words, we
cannot guarantee that Monit will run on a specific time. Therefor we
strongly recommend to use an asterix in the minute field or at minimum
a range, e..g. 0-15. Never use a specific minute as Monit may not run
on that minute.

We will address this limitation in a future release and convert the
scheduler from serial polling into a parallel non-blocking scheduler
where checks are guaranteed to run on time and with seconds resolution.

SERVICE GROUPS
Service entries in the control file, monitrc, can be grouped together
by the group statement. The syntax is simply (keyword in capital):

GROUP groupname

With this statement it is possible to group similar service entries
together and manage them as a whole. Monit provides functions to start,
stop, restart, monitor and unmonitor a group of services, like so:

To start a group of services from the console:

monit -g <groupname> start

To stop a group of services:

monit -g <groupname> stop

To restart a group of services:

monit -g <groupname> restart

A service can be added to multiple groups by using more than one group
statement:

group www
group filesystem

SERVICE MONITORING MODE
Monit supports three monitoring modes per service: active, passive and
manual.

Syntax:

MODE <ACTIVE | PASSIVE | MANUAL>

In active mode (the default), Monit will pro-actively monitor a service
and in case of problems raise alerts and/or restart the service.

In passive mode, Monit will passively monitor a service and will raise
alerts, but will not try to fix a problem by executing start, stop or
restart.

In manual mode, Monit will enter active mode only if a service was
started via Monit:

monit start <servicename>

Use "monit stop <servicename>" to stop the service and take it out of
Monit's control. The manual mode can be used to build a simple cluster
with active/passive HA-services.

A service's monitoring state is persistent across Monit restart.

If you use Monit in a HA-cluster you should place the Monit state file
in a temporary filesystem so if the machine which runs HA-services
should crash and the stand-by machine take over its services, the HA-
services won't be started after the crashed node will boot again:

set statefile /tmp/monit.state

SERVICE RESTART LIMIT
Monit provides a restart limit mechanism for situations where a service
simply refuses to start or respond over a longer period.

The restart limit mechanism is based on number of service restarts and
number of poll-cycles. For example, if a service had x restarts within
y poll-cycles (where x <= y) then Monit will perform an action (for
example unmonitor the service). If a timeout occurs, Monit will send an
alert message if you have register interest for this event.

The syntax for the timeout statement is as follows (keywords are in
capital):

IF <number> RESTART <number> CYCLE(S) THEN <action>

The action value is either one of common actions or TIMEOUT (for
backward compatibility, equals to UNMONITOR action).

Here is an example where Monit will unmonitor the service if it was
restarted 2 times within 3 cycles:

if 2 restarts within 3 cycles then unmonitor

To have Monit check the service again after monitoring was disabled,
run "monit monitor servicename" from the command line.

Example for setting custom exec on timeout:

if 5 restarts within 5 cycles then exec "/foo/bar"

Example for stopping the service:

if 7 restarts within 10 cycles then stop

SERVICE DEPENDENCIES
If specified in the control file, Monit can do dependency checking
before start, stop, monitoring or unmonitoring of services. The
dependency statement may be used within any service entries in the
Monit control file.

The syntax for the depend statement is simply:

DEPENDS on service[, service [,...]]

Where service is a check service entry name used in your ".monitrc"
file, for instance apache or datafs.

You may add more than one service name of any type or use more than one
depend statement in an entry.

Services specified in a depend statement will be checked during
stop/start/monitor/unmonitor operations.

If a service is stopped or unmonitored it will stop/unmonitor any
services that depends on itself.

If the service is started, all services which this service depends on
will be started before starting this service. if start of some service
failed, the service with prerequisites will NOT be started and the, but
will remember that it should start and will retry next cycle.

If a service is restarted, it will first stop any active services that
depend on it and after it is started, start all depending services that
were active before the restart again.

Here is an example where we set up an apache service entry to depend on
the underlying apache binary. If the binary should change an alert is
sent and apache is not monitored anymore. The rationale is security and
that Monit should not execute a possibly cracked apache binary.

(1) check process apache with pidfile "/var/run/httpd.pid"
(2) depends on httpd
(3) ...
(4)
(5) check file httpd with path /usr/bin/httpd
(6) if failed checksum then stop

The first entry is the process entry for apache. The second line sets
up a dependency between this entry and the service entry named httpd in
line 5. A dependency tree works as follows, if an action is conducted
in a lower branch it will propagate upward in the tree and for every
dependent entry execute the same action. In this case, if the checksum
should fail in line 6 then an stop action is executed and apache binary
is not checked anymore. But since the apache process entry depends on
the httpd entry this entry will also execute the stop action. In short,
if the checksum test for the httpd binary file should fail, both the
check file httpd and the check process apache entry are stopped.

A dependency tree is a general construct and can be used between all
types of service entries and span many levels and propagate any
supported action (except the exec action which will not propagate
upward in a dependency tree for obvious reasons).

Here is another different example. Consider the following common server
setup:

WEB-SERVER -> APPLICATION-SERVER -> DATABASE -> FILESYSTEM
(a) (b) (c) (d)

You can set dependencies so that the web-server depends on the
application server to run before the web-server starts and the
application server depends on the database server and the database
depends on the filesystem to be mounted before it starts. See also the
example section below for examples using the depend statement.

Here we describe how Monit will function with the above dependencies:

If no services are running
Monit will start the servers in the following order: d, c, b, a

If all servers are running
When you run 'monit stop all' this is the stop order: a, b, c, d.
If you run 'Monit stop d' then a, b and c are also stopped because
they depend on d and finally d is stopped.

If a does not run
Monit will start a

If b does not run
Monit will first stop a then start b and finally start a if b is up
again.

If c does not run
Monit will first stop a and b then start c and finally start b then
a.

If d does not run
Monit will first stop a, b and c then start d and finally start c,
b then a.

If the control file contains a depend loop.
A depend loop is for example; a->b and b->a or a->b->c->a.

When Monit starts it will check for such loops and complain and
exit if a loop was found. It will also exit with a complaint if a
depend statement was used that does not point to a service in the
control file.

SERVICE TESTS
GENERAL SYNTAX

Monit provides several tests you can use in a 'check' statement to test
a service.

You can test either for some expected value or range and take actions
if the value changed.

General syntax for testing a specific value or range:

IF <TEST> THEN ACTION [ELSE IF SUCCEEDED THEN ACTION]

The action is evaluated each time the <TEST> condition is true. Success
action is optional and executed only when the state changes from
failure to success. If success action is not set, Monit will send a
recovery alert by default.

General syntax for a value change test:

IF CHANGED <TEST> THEN ACTION

The action is executed each time the value changes. Monit will remember
the new value and will trigger event if the value change again.

ACTION

In each test you must select the action to be executed from this list:

· ALERT sends the user an alert event on each state change.

· RESTART restarts the service and send an alert. Restart is
performed by calling the service's registered restart method or by
first calling the stop method followed by the start method if
restart is not set.

· START starts the service by calling the service's registered start
method and send an alert.

· STOP stops the service by calling the service's registered stop
method and send an alert. If Monit stops a service it will not be
checked by Monit anymore nor restarted again later. To reactivate
monitoring of the service again you must explicitly enable
monitoring from the web interface or from the console.

· EXEC can be used to execute an arbitrary program and send an alert.
If you choose this action you must state the program to be executed
and if the program require arguments you must enclose the program
and its arguments in a quoted string. You may optionally specify
the uid and gid the executed program should switch to upon start.
For instance:

exec "/usr/local/tomcat/bin/startup.sh"
as uid nobody and gid nobody

Remember, if Monit is run by root, then all programs executed by
Monit will be started with superuser privileges unless the uid and
gid extension is used.

· UNMONITOR will disable monitoring of the service and send an alert.
The service will not be checked by Monit anymore nor restarted
again later. To reactivate monitoring of the service you must
explicitly enable monitoring from the web interface or from the
console.

FAILURE TOLERANCE

By default the action is executed if it matches and the service set in
an error state. However, you can require a test to fail more than once
before the error event is triggered and the service state changed to
failed. This is useful to avoid getting alerts on spurious errors,
which can happen, especially with network tests.

Syntax:

FOR <X> CYCLES ...

or:

<X> [TIMES WITHIN] <Y> CYCLES ...

The condition can be used both for failure and success action.

The first, simpler and recommended format requires "X" consecutive
events before switching the state:

if failed
port 80
for 3 cycles
then alert

The second format is more advanced and allows to tolerate intermittent
issues, but still catch excessive problems, where the service is
flapping between error and success states frequently.

For example if every second cycle fails (1-0-1-0-1-0-...), then "for 2
cycles" condition will never match, despite the service having
problems. The following statement will catch such a state:

if failed
port 80
for 3 times within 5 cycles
then alert

Example which sets multiple error levels and actions:

check filesystem rootfs with path /dev/hda1
if space usage > 80% for 5 times within 15 cycles then alert
if space usage > 90% for 5 cycles then exec '/try/to/free/the/space'

Note: the maximum value for cycles is 64.

EXISTENCE TESTING
This test is always active for the process, file, directory and fifo
checks and is if not defined, it defaults to a restart action.

You can override the default action with the following statement:

IF [DOES] NOT EXIST THEN action

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

Example:

check file with path /cifs/mydata
if does not exist then exec "/usr/bin/mount_cifs.sh"

RESOURCE TESTING
Monit can examine how much system resources a service is using. This
test can only be used within a system or process service entry in the
Monit control file.

Depending on system or process characteristics, services can be stopped
or restarted and alerts can be generated. Thus it is possible to
utilise systems which are idle and to spare system under high load.

The full syntax for a resource-statement used for resource testing is
as follows (keywords are in capital and optional statements in
[brackets]),

IF resource operator value THEN action

resource is a choice of "CPU", "TOTAL CPU", "CPU([user|system|wait])",
"MEMORY", "SWAP", "CHILDREN", "TOTAL MEMORY",
"LOADAVG([1min|5min|15min])". Some resource tests can be used inside a
check system entry, some in a check process entry and some in both:

System only resource tests:

CPU([user|system|wait]) is the percent of time the system spend in user
or kernel space and I/O. The user/system/wait modifier is optional, if
not used, the total system cpu usage is tested.

SWAP is the swap usage of the system in either percent (of the systems
total) or as an amount (Byte, kB, MB, GB).

Process only resource tests:

CPU is the CPU usage of the process itself (percent).

TOTAL CPU is the total CPU usage of the process and its children in
(percent). You will want to use TOTAL CPU typically for services like
Apache web server where one master process forks child processes as
workers.

CHILDREN is the number of child processes of the process.

TOTAL MEMORY is the memory usage of the process and its child processes
in either percent or as an amount (Byte, kB, MB, GB).

System and process resource tests:

MEMORY is the memory usage of the system or of a process (without
children) in either percent (of the systems total) or as an amount
(Byte, kB, MB, GB).

LOADAVG([1min|5min|15min]) refers to the system's load average. The
load average is the number of processes in the system run queue,
averaged over the specified time period.

operator is a choice of "<", ">", "!=", "==" in C notation, "gt", "lt",
"eq", "ne" in shell sh notation and "greater", "less", "equal",
"notequal" in human readable form (if not specified, default is EQUAL).

value is either an integer or a real number (except for CHILDREN). For
CPU, TOTAL CPU, MEMORY and TOTAL MEMORY you need to specify a unit.
This could be "%" or if applicable "B" (Byte), "kB" (1024 Byte), "MB"
(1024 KiloByte) or "GB" (1024 MegaByte).

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

To calculate the cycles, a counter is raised whenever the expression
above is true and it is lowered whenever it is false (but not below 0).
All counters are reset in case of a restart.

The following is an example to check that the CPU usage of a service is
not going beyond 50% during five poll cycles. If it does, Monit will
restart the service:

if cpu is greater than 50% for 5 cycles then restart

FILE CHECKSUM TESTING
The checksum statement may only be used in a file service entry and can
be used to check the file's MD5 or SHA1 checksum.

Check specific checksum:

IF FAILED [MD5|SHA1] CHECKSUM [EXPECT checksum] THEN action

Check any file changes:

IF CHANGED [MD5|SHA1] CHECKSUM THEN action

The choice of MD5 or SHA1 is optional. MD5 features a 128 bits checksum
(32 bytes hex encoded string) and SHA1 a 160 bits checksum (40 bytes
hex encoded string). If this option is omitted, Monit will try to guess
the method from the EXPECT string or use MD5 as the default checksum.

"expect" is optional and if used, specifies the md5 or sha1 string
Monit should expect when testing a file's checksum. Monit will then not
compute an initial checksum for the file, but instead use the string
you submit. For example:

if failed
checksum expect 8f7f419955cefa0b33a2ba316cba3659
then alert

You can, for example, use the GNU utility md5sum(1) or sha1sum(1) to
create a checksum string for a file and use this string in the expect-
statement.

Reloading a server if its configuration file was changed:

check file apache_conf with path /etc/apache/httpd.conf
if changed checksum then exec "/usr/bin/apachectl graceful"

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

TIMESTAMP TESTING
The timestamp statement may only be used in a file, fifo or directory
service entry.

Specific timestamp syntax:

IF TIMESTAMP [[operator] value [unit]] THEN action

Timestamp changed syntax:

IF CHANGED TIMESTAMP THEN action

operator is a choice of "<", ">", "!=", "==" in C notation, "GT", "LT",
"EQ", "NE" in shell sh notation and "GREATER", "LESS", "EQUAL",
"NOTEQUAL" in human readable form (if not specified, default is EQUAL).

value is a time watermark.

unit is either "SECOND(S)", "MINUTE(S)", "HOUR(S)" or "DAY(S)".

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

For example to reload apache if the configuration file timestamp
changed:

check file apache_conf with path /etc/apache/httpd.conf
if changed timestamp then exec "/usr/bin/apachectl graceful"

For example testing directory for file addition or removal:

check directory bar path /foo/bar
if timestamp < 1 hour then alert

FILE SIZE TESTING
The size statement may only be used in a check file service entry. If
specified in the control file, Monit will compute a size for a file.

Testing specific size or range:

IF SIZE [[operator] value [unit]] THEN action

Testing size changes:

IF CHANGED SIZE THEN action

value is a size watermark.

unit is a choice of "B","KB","MB","GB" or long alternatives "byte",
"kilobyte", "megabyte", "gigabyte". If it is not specified, "byte" unit
is assumed by default.

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

For example to send an alert if the file is too large:

check file mydb with path /data/mydatabase.db
if size > 1 GB then alert

FILE CONTENT TESTING
The match statement can be used to incrementally test the content of a
text file by using regular expressions.

Syntax:

IF [NOT] MATCH {regex|path} THEN action

regex is a string containing the extended regular expression. See also
regex(7).

path is an absolute path to a file containing extended regular
expression on every line. See also regex(7).

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

You can use the NOT statement to invert a match.

On startup the read position is set to the end of the file and Monit
continues to scan to the end of the file on each cycle.

If the file size should decrease or inode changed, the read position is
set to the start of the file.

Only lines ending with a newline character are inspected.

Only the first 511 characters of a line are inspected.

IGNORE [NOT] MATCH {regex|path}

Lines matching an IGNORE are not inspected during later evaluations.
IGNORE MATCH has always precedence over IF MATCH.

All IGNORE MATCH statements are evaluated first, in the order of their
appearance. Thereafter, all the IF MATCH statements are evaluated.

For example:

check file syslog with path /var/log/syslog
ignore match "^monit"
if match "^mrcoffee" then alert

FILESYSTEM FLAGS TESTING
Monit can test the flags of a filesystem for changes. This test is
implicit and Monit will send alert in case of failure by default.

This test is useful for detecting changes of filesystem flags such as
if the filesystem become read-only (on disk error) or mount flags were
changed (such as nosuid).

The syntax for the fsflags statement is:

IF CHANGED FSFLAGS THEN action

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

Example:

check filesystem rootfs with path /
if changed fsflags then exec "/my/script"

SPACE TESTING
Monit can test a filesystem or a disk for space usage. This test may
only be used in the context of a filesystem service type.

Filesystems usually have some space reserved for the root user (ca.
1-5%), so non-superusers cannot write to a nearly full filesystem. If
you set a limit for the filesystem which is used by non-root users you
might want to consider these reserved blocks when setting the limit.
You can use Monit itself to view the reserved blocks percentage by
using the CLI status command or the HTTP interface for the given
filesystem.

Syntax:

IF SPACE operator value unit THEN action

or:

IF SPACE FREE operator value unit THEN action

operator is a choice of "<",">","!=","==" in c notation, "gt", "lt",
"eq", "ne" in shell sh notation and "greater", "less", "equal",
"notequal" in human readable form (if not specified, default is EQUAL).

unit is a choice of "B","KB","MB","GB", "%" or long alternatives
"byte", "kilobyte", "megabyte", "gigabyte", "percent".

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

Example:

check filesystem rootfs with path /
if space usage > 90% then alert

INODE TESTING
Monit can test filesystem inode usage. This test may only be used in
the context of a filesystem service type.

Syntax:

IF INODE(S) operator value [unit] THEN action

or:

IF INODE(S) FREE operator value [unit] THEN action

unit is optional. If not specified, the value is an absolute count of
inodes. You can use the "%" character or the longer alternative
"percent" as a unit.

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

Example:

check filesystem rootfs with path /
if inode usage > 90% then alert

PERMISSION TESTING
Monit can test the permissions of file objects. This test may only be
used in the context of a file, fifo, directory or filesystem service
types.

Syntax for testing specific permissions:

IF FAILED PERM(ISSION) octalnumber THEN action

Syntax for testing any permission change:

IF CHANGED PERM(ISSION) THEN action

octalnumber defines permissions for a file, a directory or a filesystem
as four octal digits (0-7). Valid range is 0000 - 7777 (you can omit
the leading zeros, Monit will add the zeros to the left. For example,
"640" is a valid value and matches "0640").

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

Example:

check file shadow with path /etc/shadow
if failed permission 0640 then alert

UID TESTING
Monit can monitor the owner user id (uid) of a file, fifo, directory or
owner and effective user of a process.

Syntax:

IF FAILED [E]UID user THEN action

user defines a user id either in numeric or in string form.

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

Example:

check file shadow with path /etc/shadow
if failed uid root then alert

GID TESTING
Monit can monitor the owner group id (gid) of a file, fifo, directory
or process.

Syntax:

IF FAILED GID group THEN action

group defines a group id either in numeric or in string form.

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

Example:

check file shadow with path /etc/shadow
if failed gid shadow then alert

PID TESTING
Monit can test the process' PID. This test is implicit and Monit will
send an alert in case the PID changed outside of Monit's control.

Syntax:

IF CHANGED PID THEN action

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

This test is useful to detect possible process restarts which has
occurred in the timeframe between two Monit testing cycles.

For example if someone changes sshd configuration and did sshd restart
outside of Monit's control you will be notified that the process was
replaced by a new instance:

check process sshd with pidfile /var/run/sshd.pid
if changed pid then alert

PPID TESTING
Monit can test the process' parent PID (PPID) for changes. This test is
implicit and Monit will send alert in the case that the PPID changed
outside of Monit control.

The syntax for the ppid statement is:

IF CHANGED PPID THEN action

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

Example:

check process myproc with pidfile /var/run/myproc.pid
if changed ppid then exec "/my/script"

PROCESS UPTIME TESTING
The uptime statement may only be used in a process service type
context.

Syntax:

IF UPTIME [[operator] value [unit]] THEN action

value is a uptime watermark.

unit is either "SECOND", "MINUTE", "HOUR" or "DAY" (it is also possible
to use "SECONDS", "MINUTES", "HOURS", or "DAYS").

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

Example of restarting the process every three days:

check process myapp with pidfile /var/run/myapp.pid
start program = "/etc/init.d/myapp start"
stop program = "/etc/init.d/myapp stop"
if uptime > 3 days then restart

PROGRAM STATUS TESTING
You can check the exit status of a program or a script. This test may
only be used within a check program service entry in the Monit control
file.

Syntax for testing specific exit value:

IF STATUS operator value THEN action

Syntax for testing any exit value change:

IF CHANGED STATUS THEN action

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

Example:

check program myscript with path /usr/local/bin/myscript.sh
if status != 0 then alert

Sample script for the above example (/usr/local/bin/myscript.sh):

#!/bin/bash
echo test
exit $?

You can also send parameters with the program:

check program list-files with path "/bin/ls -lrt /tmp/"
if status != 0 then alert

Arguments to the program or script is a sequence of whitespace
separated strings. In the above example the strings '-lrt' and '/tmp/'
are arguments to the program '/bin/ls'. If arguments are used, it is
recommended to use quotes " to enclose the string, otherwise, if no
arguments are used, quotes are not needed.

Notes: If the program is a script, the interpreter is required in the
first line. The program or script must also be executable.

If Monit is run as the super user, you can optionally run the program
as a different user and/or group. In this example we run the ls program
as user www and as group staff:

check program ls with path "/bin/ls /tmp" as uid "www"
and gid "staff"
if status != 0 then alert

Monit will execute the program periodically and if the exit status of
the program does not match the expected result, Monit can perform an
action. In the example above, Monit will raise an alert if the exit
value is different from 0. By convention, 0 means the program exited
normally.

Program checks are asynchronous. Meaning that Monit will not wait for
the program to exit, but instead, Monit will start the program in the
background and immediately continue checking the next service entry in
monitrc. At the next cycle, Monit will check if the program has
finished and if so, collect the program's exit status. If the status
indicate a failure, Monit will raise an alert message containing the
program's error (stderr) output, if any. If the program has not exited
after the first cycle, Monit will wait another cycle and so on. If the
program is still running after 5 minutes, Monit will kill it and
generate a program timeout event. It is possible to override the
default timeout (see the syntax below).

The asynchronous nature of the program check allows for non-blocking
behaviour in the current Monit design, but it comes with a side-effect:
when the program has finished executing and is waiting for Monit to
collect the result, it becomes a so-called "zombie" process. A zombie
process does not consume any system resources (only the PID remains in
use) and it is under Monit's control and the zombie process is removed
from the system as soon as Monit collects the exit status. This means
that every "check program" will be associated with either a running
process or a temporary zombie. This unwanted zombie side-effect will be
removed in a later release of Monit.

Multiple status tests can be used, for example:

check program hwtest with path /usr/local/bin/hwtest.sh
with timeout 500 seconds
if status = 1 then alert
if status = 3 for 5 cycles then exec "/usr/local/bin/emergency.sh"

NETWORK LINK STATUS TEST
You can check the network link state. This test may only be used within
a check network service entry in the Monit control file.

Syntax:

IF FAILED LINK THEN action

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

The test will fail if the link/interface is down or link errors were
detected.

Example:

check network eth0 with interface eth0
if failed link then alert

In case a link failed you can add a start and stop program to
automatically restart the interface which might help. (Substitute with
the relevant network commands for your system)

check network eth0 with interface eth0
start program = '/sbin/ipup eth0'
stop program = '/sbin/ipdown eth0'
if failed link then restart

NETWORK LINK CAPACITY TEST
You can check the network link mode capacity for changes. This test may
only be used within a check network service entry in the Monit control
file.

Syntax:

IF CHANGED LINK [CAPACITY] THEN action

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

The test will match if the link mode has changed (e.g. maximum speed
dropped) or if the duplex mode has changed.

NOTE: not all interface types allow for capacity monitoring. Pseudo
interfaces such as loopback device or VMWare interfaces does not have a
speed attribute.

Example:

check network eth0 with interface eth0
if changed link capacity then alert

NETWORK SATURATION TEST
You can check the network link saturation. Monit then computes the link
utilisation based on the current transfer rate vs. link capacity. This
test may only be used within a check network service entry in the Monit
control file.

Syntax:

IF SATURATION operator value% THEN action

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

NOTE: this test depends on the availability of the speed attribute and
not all interface types have this attribute. See the LINK SPEED test
description.

Example:

check network eth0 with interface eth0
if saturation > 90% then alert

NETWORK BANDWIDTH TEST
You can check a network link upload and download bandwidth usage,
current transfer rate and total data transferred in the last 24 hours.
This test may only be used within a check network service entry in the
Monit control file.

Warning: this test requires monit poll time to be at maximum 30
seconds.

Current upload bandwidth rate test syntax:

IF UPLOAD operator value unit THEN action

Current download bandwidth rate test syntax:

IF DOWNLOAD operator value unit THEN action

Total upload test syntax:

IF TOTAL UPLOAD operator value unit IN LAST number time-unit THEN action

Total download test syntax:

IF TOTAL DOWNLOAD operator value unit IN LAST number time-unit THEN action

unit is a choice of "B","KB","MB","GB" or long alternatives "byte",
"kilobyte", "megabyte", "gigabyte".

time-unit is a choice of "MINUTE(S)", "HOUR(S)", "DAY". NOTE: Monit
maintains a rolling count of total uploaded and downloaded bytes for
the last 24 hours only. The value of time-unit can therefor not specify
a range wider than one day.

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

Examples:

check network eth0 with interface eth0
if upload > 500 kB/s then alert
if total download > 1 GB in last 2 hours then alert
if total download > 10 GB in last day then alert

NETWORK PACKETS TEST
You can check the network link upload and download packets count,
current transfer rate and total data transferred in last 24 hours. This
test may only be used within a check network service entry in the Monit
control file.

Warning: this test requires monit poll time to be at maximum 30
seconds.

Current upload bandwidth rate test syntax:

IF UPLOAD operator value PACKETS/S THEN action

Current download bandwidth rate test syntax:

IF DOWNLOAD operator value PACKETS/S THEN action

Total upload test syntax:

IF TOTAL UPLOAD operator value PACKETS IN LAST number time-unit THEN action

Total download test syntax:

IF TOTAL DOWNLOAD operator value PACKETS IN LAST number time-unit THEN action

time-unit is a choice of "MINUTE(S)", "HOUR(S)", "DAY". NOTE: Monit
keeps total upload/download statistics only for the last 24 hours. The
time-unit value cannot therefor span more than one day.

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

Examples:

check network eth0 with interface eth0
if upload > 1000 packets/s then alert
if total upload > 900000 packets in last hour then alert

NETWORK PING TEST
Monit can perform a network ping test by sending ICMP echo request
datagram packets to a host and wait for the reply. This test can only
be used within a check host statement. Monit must also run as the root
user in order to be able to perform the ping test (because the ping
test must use raw sockets which usually only the super user is allowed
to).

Syntax:

IF FAILED PING[4|6]
[COUNT number] [SIZE number] [WITH] [TIMEOUT number SECONDS]
THEN action

If a DNS host name was used in the check host statement and the host
name resolve to several addresses (either IPv4 or IPv6), Monit will
ping the first available address and continue with the next address
until one connection succeed or until there are no more addresses left
to try. You can force Monit to only ping IPv4 or IPv6 addresses by
using the PING4 or the PING6 keyword instead of PING.

The COUNT parameter specifies how many consecutive ping requests will
be sent to the host in one cycle at maximum. The default value is 3.

The SIZE parameter specifies the ping request data size. Default is 64
bytes.

If no reply arrive within TIMEOUT seconds, Monit reports an error. If
at least one reply was received, the ping test is considered a success.

Monit will, by default, send up to three ping request packets in one
cycle to prevent false alarm (i.e. up to 66% packet loss is tolerated).
You can set the COUNT option to a value between 1 and 20 to send more
or fewer packets. If you require 100% ping success, set the count to 1
(i.e. just one request will be sent, and if the packet was lost an
error will be reported).

Note that many ISPs have started to filter out ping or ICMP packets
now, in which case there will be no reply from the host.

If a ping test is used in a check host entry, this test is run first
and if the test should fail, we assume that the connection to the host
is down and Monit will not continue with any subsequent port tests.

Example:

check host mmonit.com with address mmonit.com
if failed ping then alert # IPv4 or IPv6

check host mmonit.com with address 62.109.39.247
if failed ping then alert # Address is IPv4 so IPv4 is preferred

or test that the system is explicit accessible via IPv4 and IPv6:

check host mmonit.com with address mmonit.com
if failed ping4 then alert # IPv4 only
if failed ping6 then alert # IPv6 only

or with all parameters; Send five 128 byte pings to mmonit.com and wait
for up to 10 seconds for a reply

check host mmonit.com with address mmonit.com
if failed ping count 5 size 128 with timeout 10 seconds then alert

CONNECTION TESTING
Monit can perform connection testing via network ports or via Unix
sockets. A connection test may only be used within a process or host
service type context.

If a service listens on one or more sockets, Monit can connect to the
port (using TCP or UDP) and verify that the service will accept a
connection and that it is possible to write and read from the socket.
If a connection is not accepted or if there is a problem with socket
I/O, Monit will execute a specified action.

TCP/UDP port test syntax:

IF FAILED
[host]
<port>
[ipversion]
[type]
[ssl [with options {...}]]
[certificate checksum]
[certificate valid days]
[protocol | {send/expect}+]
[timeout]
[retry]
THEN action

Unix socket test syntax:

IF FAILED
<unixsocket>
[type]
[protocol | {send/expect}+]
[timeout]
[retry]
THEN action

Examples:

if failed port 80 then alert

if failed port 53 type udp protocol dns then alert

if failed unixsocket /var/run/sophie then alert

Options:

host: HOST hostname. Optionally specify the host to connect to. If the
host is not given then localhost is assumed if this test is used inside
a process entry. If this test is used inside a remote host entry then
the entry's remote host is assumed.

port: PORT number. The port number to connect to

unixsocket: UNIXSOCKET path. Specifies the path to a Unix socket (local
machine only).

ipversion: IPV4 | IPV6 . Optionally specify the IP version Monit should
use when trying to connect to the port. If not used, Monit will try to
connect to the first available address (IPv4 or IPv6). If multiple
addresses are available and connection to one address failed, Monit
will try the next address and so on until a connection succeed or until
there are no more addresses left to try.

type: TYPE [TCP | UDP]. Optionally specify the socket type Monit should
use when trying to connect to the port. The different socket types are:
TCP or UDP, where TCP is a regular stream based socket, UDP, a datagram
socket. The default socket type is TCP.

ssl: [SSL | TLS] [with options {...}]. Set SSL/TLS options and override
global/default SSL options. You can set the SSL/TLS version to use,
whether to verify certificates, trust self-signed certificates or set
the SSL client certificates database-file for client certificate
authentication.

certificate checksum: CERTIFICATE CHECKSUM [MD5|SHA1] hash. Verify the
SSL server certificate by checking its checksum. You can use either MD5
or SHA1 checksum (if you don't specify the type, Monit will determine
the digest based on the hash length). You can use the openssl command
line tool to get the checksum value for your certificate, which you can
then use in Monit's control file:

openssl x509 -fingerprint -sha1 -in server.crt | head -1 | cut -f2 -d'='

Example:

if failed
port 443
protocol https
and certificate checksum = "1ED948A6F4258ACAB964227EF4EB19FCC453B0F8"
then alert

certificate expire days: CERTIFICATE VALID for number DAYS. Send an
alert if the certificate will expire in the given number of days. This
test is pretty useful to get a notification when it is time to renew
your SSL certificate.

Example:

if failed
port 443
protocol https
and certificate valid > 30 days
then alert

protocol: PROTO(COL) protocol. Optionally specify the protocol Monit
should speak when a connection is established. At the moment Monit
knows how to speak:
APACHE-STATUS
DNS
DWP
FTP
GPS
HTTP
HTTPS
IMAP
IMAPS
CLAMAV
LDAP2
LDAP3
LMTP
MEMCACHE
MONGODB
MYSQL
NNTP
NTP3
PGSQL
POP
POPS
POSTFIX-POLICY
RADIUS
RDATE
REDIS
RSYNC
SIEVE
SIP
SMTP
SMTPS
SSH
TNS
WEBSOCKET

If the target server's protocol is not found in this list, simply do
not specify the protocol and Monit will use a default connection test.

timeout: [WITH] TIMEOUT number SECONDS. Optionally specifies the
connect and read timeout for the connection. If Monit cannot connect to
the server within this time it will assume that the connection failed
and execute the specified action. The default connect timeout is 5
seconds.

retry: RETRY number. Optionally specifies the number of consecutive
retries within the same testing cycle in the case that the connection
failed. The default is fail on first error.

action is a choice of "ALERT", "RESTART", "START", "STOP", "EXEC" or
"UNMONITOR".

Specific protocol test options

GENERIC (SEND/EXPECT)

If Monit does not support the protocol spoken by the server, you can
write your own protocol-test using send and expect strings. The SEND
statement sends a string to the server port and the EXPECT statement
compares a string read from the server with the string given in the
expect statement.

Syntax:

[{SEND|EXPECT} "string"]+

Monit will send a string as it is, and you must remember to include CR
and LF in the string sent to the server if the protocol expects such
characters to terminate a string (most text based protocols used over
Internet do).

Monit will by default read up to 255 bytes from the server and use this
string when comparing the EXPECT string. You can override the default
value by using this statement at the top of the Monit configuration
file:

SET EXPECTBUFFER <number> ["b"|"kb"]

Max value for the expect buffer is 100 kb. For example, to set the
expect buffer to read 10 kilobytes:

set expectbuffer 10 kb

You can use non-printable characters in a SEND string if needed. Use
the hex notation, \0xHEXHEX to send any char in the range \0x00-\0xFF,
that is, 0-255 in decimal. For example, to test a Quake 3 server:

send "\0xFF\0xFF\0xFF\0xFFgetstatus"
expect "sv_floodProtect|sv_maxPing"

If your system supports POSIX regular expressions, you can use regular
expressions in the EXPECT string, see regex(7) to learn more about the
types of regular expressions you can use in an expect string.

Since both regex and string compare operates on a zero terminated
string, you cannot test for '\0' in an EXPECT buffer since this
character marks the end of the buffer. However, we escape '\0' in the
expect buffer as "\0" which you can test for. That is, '\' followed by
the ascii value for 0. For instance, here is how to test for an expect
string that starts with zero followed by any number of characters.

expect "^[\\]0.*"

Here is a simple SMTP protocol example:

if failed
port 25 and
expect "^220.*"
send "HELO localhost.localdomain\r\n"
expect "^250.*"
send "QUIT\r\n"
then alert

SEND/EXPECT can be used with any socket type, such as TCP sockets, UNIX
sockets and UDP sockets.

HTTP

Syntax:

PROTO(COL) HTTP
[REQUEST "string"]
[STATUS operator number]
[CHECKSUM checksum]
[HTTP HEADERS list of headers]
[CONTENT {= | != } STRING]

REQUEST option can set an URL string specifying a document on the HTTP
server. If the request statement isn't specified, the default "/" page
will be requested.

For example:

if failed
port 80
protocol http
request "/data/show?a=b&c=d"
then restart

STATUS option can be used to explicitly test the HTTP status code
returned by the HTTP server. If not used, the HTTP protocol test will
fail if the status code returned is greater than or equal to 400. You
can override this behaviour by using the status qualifier.

For example to test that a page does not exist (the HTTP server should
return 404 in this case):

if failed
port 80
protocol http
request "/non/existent.php"
status = 404
then alert

CHECKSUM You can test the checksum of documents returned by a HTTP
server. Either MD5 or SHA1 hash can be used. Monit will not test the
checksum for a document if the server does not set the HTTP Content-
Length header. A HTTP server should set this header when it server a
static document (i.e. a file). There are no limitation on the document
size, but keep in mind that Monit will use time to download the
document over the network to compute the checksum.

Example:

if failed
port 80
protocol http
request "/page.html"
checksum 8f7f419955cefa0b33a2ba316cba3659
then alert

HTTP HEADERS can be used to send a list of any HTTP headers with a HTTP
protocol test. For instance, the host header. If the host header is not
set, Monit will use the hostname or IP-address of the host as specified
in the check host statement. Specifying a host header is useful if you
want to connect to and test a name-based virtual host. The syntax for
setting HTTP headers is

http headers [name:value, name:value,..]

where each name:value pair is separated with ','. If you need to use
':' in the value string, for instance to set port number for a host
header, you must enclose the value in quotes. For example,

http headers [Host: "mmonit.com:443"]

In a check host context, using this statement might look like

check host mmonit.com with address mmonit.com
if failed
port 80 protocol http
with http headers [Host: mmonit.com, Cache-Control: no-cache,
Cookie: csrftoken=nj1bI3CnMCaiNv4beqo8ZaCfAQQvpgLH]
and request /monit/ with content = "Monit [0-9.]+"
then alert

Setting HTTP headers is associated with the HTTP protocol test and must
come before request as in the example above.

CONTENT option sets the pattern which is expected in the data returned
by the server. If the pattern doesn't match, event is triggered.

For example:

if failed
port 80
protocol http
content = "foobar [0-9.]+"
then alert

APACHE-STATUS

The APACHE-STATUS test allows to check server performance by
examination of the status page generated by Apache's mod_status, which
is expected to be at its default address of
http://www.example.com/server-status.

Syntax:

PROTOCOL APACHE-STATUS <limit operator number>+

limit is acronym for child status:

(1) logging (loglimit)
(2) closing connections (closelimit)
(3) performing DNS lookups (dnslimit)
(4) in keepalive with a client (keepalivelimit)
(5) replying to a client (replylimit)
(6) receiving a request (requestlimit)
(7) initialising (startlimit)
(8) waiting for incoming connections (waitlimit)
(9) gracefully closing down (gracefullimit)
(10) performing cleanup procedures (cleanuplimit)

operator is one of "<", "=", ">".

number is percentile numeric limit.

Each of these limits can be compared against a value relative to the
total number of active Apache child processes.

You can combine all of these tests into one expression or you can
choose to test a certain limit only. If you combine the limits you must
connect them together using the OR keyword.

Example:

if failed port 80 protocol apache-status
loglimit > 10% or
dnslimit > 50% or
waitlimit < 20%
then alert

SIP

The SIP protocol is used by communication platform servers such as
Asterisk and FreeSWITCH.

Syntax:

PROTOCOL SIP [TARGET valid@uri] [MAXFORWARD n]

TARGET you may specify an alternative recipient for the message, by
adding a valid sip uri after this keyword.

MAXFORWARD Limit the number of proxies or gateways that can forward the
request to the next server. It's value is an integer in the range
0-255, set by default to 70. If max-forward = 0, the next server may
respond 200 OK (test succeeded) or send a 483 Too Many Hops (test
failed)

For example:

check host openser_all with address 127.0.0.1
if failed
port 5060 type udp protocol sip
with target "localhost:5060" and maxforward 6
then alert

RADIUS

Syntax:

PROTOCOL RADIUS [SECRET string]

SECRET you may specify an alternative secret, default is "testing123".

For example:

check process radiusd with pidfile /var/run/radiusd.pid
start program = "/etc/init.d/freeradius start"
stop program = "/etc/init.d/freeradius stop"
if failed
host 127.0.0.1 port 1812 type udp protocol radius
secret pingpong
then alert

MYSQL

Syntax:

PROTOCOL MYSQL [USERNAME string PASSWORD string]

USERNAME MySQL username (maximum 16 characters).

PASSWORD MySQL password (special characters can be used, but for non-
alphanumerics the password has to be quoted).

The credentials are optional. If no credentials are set, Monit will
perform the test using anonymous login. That may cause authentication
error to be logged in your MySQL log for higher MySQL log levels.

If credentials are set, Monit will login and perform MySQL ping. Monit
doesn't require any database privileges, it needs just database user,
we recommend to create standalone user for Monit testing, for example:

CREATE USER 'monit'@'host_from_which_monit_performs_testing' IDENTIFIED BY 'mysecretpassword';
FLUSH PRIVILEGES;

For example:

check process mysql with pidfile /var/run/mysqld/mysqld.pid
start program = "/sbin/start mysql"
stop program = "/sbin/stop mysql"
if failed
port 3306
protocol mysql username "foo" password "bar"
then alert

or with unix-socket and OS X start/stop commands

check process mysql with pidfile /var/run/mysqld/mysqld.pid
start program = "/usr/local/mysql/support-files/mysql.server start"
stop program = "/usr/local/mysql/support-files/mysql.server stop"
if failed
unixsocket /tmp/mysql.sock
protocol mysql username "foo" password "bar"
then alert

WEBSOCKET

Syntax:

PROTOCOL WEBSOCKET
[REQUEST string]
[HOST string]
[ORIGIN string]
[VERSION number]

HOST you may specify an alternative Host header

REQUEST you may specify an alternative request, default is "/"

ORIGIN you may specify an alternative origin, default is
"http://www.mmonit.com"

VERSION you may specify an alternative version, default is "0"

For example:

check host websocket.org with address "echo.websocket.org"
if failed
port 80 protocol websocket
host "echo.websocket.org"
request "/"
origin 'http://websocket.com'
version 13
then alert

CONFIGURATION EXAMPLES
The simplest form is just the check statement. In this example we check
to see if our web server is running and log a message if not:

check process nginx with pidfile /var/run/nginx.pid

To have Monit start the server if it's not running, add a start
statement:

check process nginx with pidfile /var/run/nginx.pid
start program = "/etc/init.d/nginx start"

Here's a more advanced example for monitoring an apache web-server
listening on the default port number for HTTP and HTTPS. In this
example Monit will restart apache if it's not accepting connections at
the port numbers. The method Monit use for restart is to first execute
the stop-program, then wait (up to 30s) for the process to stop and
then execute the start-program and wait (30s) for it to start. The
length of start or stop wait can be overridden using the 'timeout'
option. If Monit was unable to stop or start the service a failed alert
message will be sent if you have requested alert messages to be sent.

check process apache with pidfile /var/run/httpd.pid
start program = "/etc/init.d/httpd start" with timeout 60 seconds
stop program = "/etc/init.d/httpd stop"
if failed port 80 for 2 cycles then restart
if failed port 443 for 2 cycles then restart

This example demonstrate how you can run a program as a specified user
(uid) and with a specified group (gid). Many daemon programs can do the
uid and gid switch by themselves, but for those programs that does not
(e.g. Java programs), monit's ability to start a program as a certain
user can be very useful. In this example we start the Tomcat Java
Servlet Engine as the standard nobody user and group. Please note that
Monit can only switch uid and gid for the program if the super-user is
running Monit, otherwise Monit will simply ignore the request to change
uid and gid.

check process tomcat with pidfile /var/run/tomcat.pid
start program = "/etc/init.d/tomcat start"
as uid nobody and gid nobody
stop program = "/etc/init.d/tomcat stop"
# You can also use id numbers instead and write:
as uid 99 and with gid 99
if failed port 8080 then alert

In this example we use udp for connection testing to check if the name-
server is running:

check process named with pidfile /var/run/named.pid
start program = "/etc/init.d/named start"
stop program = "/etc/init.d/named stop"
if failed port 53 use type udp protocol dns then restart

The following example illustrates how to check if the service 'sophie'
is answering connections on its Unix domain socket:

check process sophie with pidfile /var/run/sophie.pid
start program = "/etc/init.d/sophie start"
stop program = "/etc/init.d/sophie stop"
if failed unix /var/run/sophie then restart

In this example we check an apache web-server running on localhost
which answers for several IP-based virtual hosts or vhosts, hence the
host statement before port:

check process apache with pidfile /var/run/httpd.pid
start "/etc/init.d/httpd start"
stop "/etc/init.d/httpd stop"
if failed host www.sol.no port 80 then alert
if failed host shop.sol.no port 443 then alert
if failed host chat.sol.no port 80 then alert

To make sure that Monit is communicating with a HTTP server a protocol
test can be added:

check process apache with pidfile /var/run/httpd.pid
start "/etc/init.d/httpd start"
stop "/etc/init.d/httpd stop"
if failed
host www.sol.no port 80 protocol http
then alert

This example demonstrate a different way to check a web-server using
the send/expect mechanism:

check process apache with pidfile /var/run/httpd.pid
start "/etc/init.d/httpd start"
stop "/etc/init.d/httpd stop"
if failed
host www.sol.no port 80 and
send "GET / HTTP/1.1\r\nHost: www.sol.no\r\n\r\n"
expect "HTTP/[0-9\.]{3} 200.*"
then alert

Here we ping a remote host to check if it is up and if not, send an
alert:

check host www.tildeslash.com with address www.tildeslash.com
if failed ping then alert

In the following example we ask Monit to compute and verify the
checksum for the underlying apache binary used by the start and stop
programs. If the checksum test should fail, monitoring will be disabled
to prevent possibly restarting a compromised binary:

check process apache with pidfile /var/run/httpd.pid
start program = "/etc/init.d/httpd start"
stop program = "/etc/init.d/httpd stop"
if failed host www.tildeslash.com port 80 then restart
depends on apache_bin

check file apache_bin with path /usr/local/apache/bin/httpd
if failed checksum then unmonitor

In this example we ask Monit to test a document's checksum on a remote
server. If the checksum was changed we send an alert:

check host mmonit.com with address mmonit.com
if failed
port 80 protocol http and
request "/monit/dist/monit-5.7.tar.gz"
with checksum f9d26b8393736b5dfad837bb13780786
then alert

Here are a couple of tests for some popular communication servers,
using the SIP protocol. First we test a FreeSWITCH server and then an
Asterisk server

check process freeswitch
with pidfile /usr/local/freeswitch/log/freeswitch.pid
start program = "/usr/local/freeswitch/bin/freeswitch -nc -hp"
stop program = "/usr/local/freeswitch/bin/freeswitch -stop"
if total memory > 1000.0 MB for 5 cycles then alert
if total memory > 1500.0 MB for 5 cycles then alert
if total memory > 2000.0 MB for 5 cycles then restart
if cpu > 60% for 5 cycles then alert
if failed
port 5060 type udp protocol SIP
target me@foo.bar and maxforward 10
then restart

check process asterisk
with pidfile /var/run/asterisk/asterisk.pid
start program = "/usr/sbin/asterisk"
stop program = "/usr/sbin/asterisk -r -x 'shutdown now'"
if total memory > 1000.0 MB for 5 cycles then alert
if total memory > 1500.0 MB for 5 cycles then alert
if total memory > 2000.0 MB for 5 cycles then restart
if cpu > 60% for 5 cycles then alert
if failed
port 5060 type udp protocol SIP
and target me@foo.bar maxforward 10
then restart

Some servers are slow starters, like for example Java based Application
Servers. If we want to keep the poll-cycle low (i.e. < 60 seconds) but
allow some services to take its time to start, the every statement is
handy:

check process dynamo with pidfile /etc/dynamo.pid every 2 cycles
start program = "/etc/init.d/dynamo start"
stop program = "/etc/init.d/dynamo stop"
if failed port 8840 then alert

Here is an example where we group together two database entries so you
can manage them together, e.g.; 'Monit -g database start all'. The mode
statement is also illustrated in the first entry and have the effect
that Monit will not try to (re)start this service if it is not running:

check process sybase with pidfile /var/run/sybase.pid
start = "/etc/init.d/sybase start"
stop = "/etc/init.d/sybase stop"
mode passive
group database

check process oracle with pidfile /var/run/oracle.pid
start program = "/etc/init.d/oracle start"
stop program = "/etc/init.d/oracle stop"
if failed
port 9001 protocol tns
then restart
group database

This resource checks example will send an alert if CPU usage of the
Apache's HTTP daemon and its child processes goes beyond 60% for two
cycles. Apache is restarted if the CPU usage is over 80% for five
cycles or the memory usage is over 100Mb for five cycles or if the
machines load average is more than 10 for 8 cycles:

check process apache with pidfile /var/run/httpd.pid
start program = "/etc/init.d/httpd start"
stop program = "/etc/init.d/httpd stop"
if cpu > 40% for 2 cycles then alert
if total cpu > 60% for 2 cycles then alert
if total cpu > 80% for 5 cycles then restart
if mem > 100 MB for 5 cycles then stop
if loadavg(5min) greater than 10.0 for 8 cycles then stop

This examples demonstrate the timestamp statement with exec and how you
may restart apache if its configuration file was changed.

check file httpd.conf with path /etc/httpd/httpd.conf
if changed timestamp
then exec "/etc/init.d/httpd graceful"

In this example we demonstrate usage of the extended alert statement
and a file check dependency:

check process apache with pidfile /var/run/httpd.pid
start = "/etc/init.d/httpd start"
stop = "/etc/init.d/httpd stop"
alert admin@bar on {nonexist, timeout}
with mail-format {
from: bofh@$HOST
subject: apache $EVENT - $ACTION
message: This event occurred on $HOST at $DATE.
Your faithful employee,
monit
}
if failed host www.tildeslash.com port 80 then restart
depend httpd_bin
group apache

check file httpd_bin with path /usr/local/apache/bin/httpd
alert security@bar on {checksum, timestamp,
permission, uid, gid}
with mail-format {subject: Alaaarrm! on $HOST}
if failed checksum
and expect 8f7f419955cefa0b33a2ba316cba3659
then unmonitor
if failed permission 755 then unmonitor
if failed uid root then unmonitor
if failed gid root then unmonitor
if changed timestamp then alert
group apache

In this example, we demonstrate usage of the depend statement. In this
case, we want to start oracle and apache. However, we've set up apache
to use oracle as a back end, and if oracle is restarted, apache must be
restarted as well.

check process apache with pidfile /var/run/httpd.pid
start = "/etc/init.d/httpd start"
stop = "/etc/init.d/httpd stop"
depends on oracle

check process oracle with pidfile /var/run/oracle.pid
start = "/etc/init.d/oracle start"
stop = "/etc/init.d/oracle stop"
if failed port 9001 for 5 cycles then restart

Next, we have 2 services, oracle-import and oracle-export that need to
be restarted if oracle is restarted, but are independent of each other.

check process oracle with pidfile /var/run/oracle.pid
start = "/etc/init.d/oracle start"
stop = "/etc/init.d/oracle stop"
if failed port 9001 for 3 cycles then restart

check process oracle-import
with pidfile /var/run/oracle-import.pid
start = "/etc/init.d/oracle-import start"
stop = "/etc/init.d/oracle-import stop"
depends on oracle

check process oracle-export
with pidfile /var/run/oracle-export.pid
start = "/etc/init.d/oracle-export start"
stop = "/etc/init.d/oracle-export stop"
depends on oracle

FILES
~/.monitrc
Default run control file

/etc/monitrc
If the control file is not found in the default
location and /etc contains a monitrc file, this
file will be used instead.

./monitrc
If the control file is not found in either of the
previous two locations, and the current working
directory contains a monitrc file, this file is
used instead.

~/.monit.pid
Lock file to help prevent concurrent runs (non-root
mode).

/run/monit.pid
Lock file to help prevent concurrent runs (root mode,
Linux systems, if /run directory is available).

/var/run/monit.pid
Lock file to help prevent concurrent runs (root mode,
Linux systems).

/etc/monit.pid
Lock file to help prevent concurrent runs (root mode,
systems without /var/run).

~/.monit.state
Monit saves its state to this file and utilises
information found in this file to recover from
a crash. This is a binary file and its content is
only of interest to monit. You may set the location
of this file in the Monit control file or by using
the -s switch when Monit is started.

~/.monit.id
Monit save its unique id to this file.

ENVIRONMENT
No environment variables are used by Monit. However, when Monit execute
a script or a program Monit will set several environment variables
which can be utilised by the executable. The following and only the
following environment variables are available:

MONIT_EVENT
The event that occurred on the service

MONIT_DESCRIPTION
A description of the error condition

MONIT_SERVICE
The name of the service (from monitrc) on which the event occurred.

MONIT_DATE
The time and date (RFC 822 style) the event occurred

MONIT_HOST
The host the event occurred on

The following environment variables are only available for process
service entries:

MONIT_PROCESS_PID
The process pid. This may be 0 if the process was (re)started,

MONIT_PROCESS_MEMORY
Process memory. This may be 0 if the process was (re)started,

MONIT_PROCESS_CHILDREN
Process children. This may be 0 if the process was (re)started,

MONIT_PROCESS_CPU_PERCENT
Process cpu%. This may be 0 if the process was (re)started,

SIGNALS
If a Monit daemon is running, SIGUSR1 wakes it up from its sleep phase
and forces a poll of all services. SIGTERM and SIGINT will gracefully
terminate a Monit daemon. The SIGTERM signal is sent to a Monit daemon
if Monit is started with the quit action argument.

Sending a SIGHUP signal to a running Monit daemon will force the daemon
to reinitialise itself, specifically it will reread configuration,
close and reopen log files.

Running Monit in foreground while a background Monit daemon is running
will wake up the daemon.

NOTES
This is a very silent program. Use the -v switch if you want to see
what Monit is doing, and tail -f the log file. Optionally for testing
purposes; you can start Monit with the -Iv switch. Monit will then
print debug information to the console, to stop monit in this mode,
simply press CTRL^C (i.e. SIGINT) in the same console.

The syntax (and parser) of the control file was inspired by Eric S.
Raymond et al.'s excellent fetchmail program. Some portions of this man
page also receive inspiration from the same authors.

COPYRIGHT
Copyright (C) 2001-2015 by Tildeslash Ltd. All Rights Reserved. This
product is distributed in the hope that it will be useful, but WITHOUT
any warranty; without even the implied warranty of MERCHANTABILITY or
FITNESS for a particular purpose.

SEE ALSO
GNU text utilities; md5sum(1); sha1sum(1); openssl(1); glob(7);
regex(7); http://www.mmonit.com/

October 22. 2015 www.mmonit.com MONIT(1)

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