MRTG-REFERENCE(1) mrtg MRTG-REFERENCE(1)NAMEmrtg-reference - MRTG 2.17.2 configuration reference
OVERVIEW
The runtime behaviour of MRTG is governed by a configuration file.
Run-of-the-mill configuration files can be generated with cfgmaker.
(Check cfgmaker). But for more elaborate configurations some hand-
tuning is required.
This document describes all the configuration options understood by the
mrtg software.
SYNTAX
MRTG configuration file syntax follows some simple rules:
· Keywords must start at the beginning of a line.
· Lines which follow a keyword line which start with a blank are
appended to the keyword line
· Empty Lines are ignored
· Lines starting with a # sign are comments.
· You can add other files into the configuration file using
Include: file
Example:
Include: base-options.inc
If included files are specified with relative paths, both the
current working directory and the directory containing the main
config file will be searched for the files. The current working
directory will be searched first.
If the included filename contains an asterisk, then this is taken
as a wildcard for zero or more characters, and all matching files
are included. Thus, you can use this statement to include all
files in a specified subdirectory.
Example:
Include: servers/*.cfg
In this case, you should be very careful that your wildcard pattern
does not find a match relative to the current working directory if
you mean it to be relative to the main config file directory, since
the working directory is checked for a match first (as with a
normal Include directive). Therefore, use of something like '*/*'
is discouraged.
GLOBAL KEYWORDS
WorkDir
WorkDir specifies where the logfiles and the webpages should be
created.
Example:
WorkDir: /usr/tardis/pub/www/stats/mrtg
OPTIONAL GLOBAL KEYWORDS
HtmlDir
HtmlDir specifies the directory where the html (or shtml, but we'll get
on to those later) lives.
NOTE: Workdir overrides the settings for htmldir, imagedir and logdir.
Example:
Htmldir: /www/mrtg/
ImageDir
ImageDir specifies the directory where the images live. They should be
under the html directory.
Example:
Imagedir: /www/mrtg/images
LogDir
LogDir specifies the directory where the logs are stored. This need
not be under htmldir directive.
Example:
Logdir: /www/mrtg/logs
Forks (UNIX only)
With system that supports fork (UNIX for example), mrtg can fork itself
into multiple instances while it is acquiring data via snmp.
For situations with high latency or a great number of devices this will
speed things up considerably. It will not make things faster, though,
if you query a single switch sitting next door.
As far as I know NT can not fork so this option is not available on NT.
Example:
Forks: 4
EnableIPv6
When set to yes, IPv6 support is enabled if the required libraries are
present (see the mrtg-ipv6 manpage). When IPv6 is enabled, mrtg can
talk to routers using SNMP over IPv6 and targets may be specified by
their numeric IPv6 addresses as well as by hostname or IPv4 address.
If IPv6 is enabled and the target is a hostname, mrtg will try to
resolve the hostname to an IPv6 address and, if this fails, to an IPv4
address. Note that mrtg will only use IPv4 if you specify an IPv4
address or a hostname with no corresponding IPv6 address; it will not
fall back to IPv4 if it simply fails to communicate with the target
using IPv6. This is by design.
Note that many routers do not currently support SNMP over IPv6. Use the
IPv4Only per target option for these routers.
IPv6 is disabled by default.
Example:
EnableIPv6: Yes
EnableSnmpV3
When set to yes, uses the Net::SNMP module instead of the SNMP_SESSION
module for generating snmp queries. This allows the use of SNMPv3 if
other snmpv3 parameters are set.
SNMPv3 is disabled by default.
Example:
EnableSnmpV3: yes
Refresh
How many seconds apart should the browser (Netscape) be instructed to
reload the page? If this is not defined, the default is 300 seconds (5
minutes).
Example:
Refresh: 600
Interval
How often do you call mrtg? The default is 5 minutes. If you call it
less often, you should specify it here. This does two things:
· The generated HTML page contains the right information about the
calling interval ...
· A META header in the generated HTML page will instruct caches about
the time-to-live of this page .....
In this example, we tell mrtg that we will be calling it every 10
minutes. If you are calling mrtg every 5 minutes, you can leave this
line commented out.
Example:
Interval: 10
Note that unless you are using rrdtool you can not set Interval to less
than 5 minutes. If you are using rrdtool you can set interval in the
format
Interval: MM[:SS]
Down to 1 second. Note though, setting the Interval for an rrdtool/mrtg
setup will influence the initial creation of the database. If you
change the interval later, all existing databases will remain at the
resolution they were initially created with. Also note that you must
make sure that your mrtg-rrd Web-frontend can deal with this kind of
Interval setting.
MaxAge
MRTG relies heavily on the real time clock of your computer. If the
time is set to a wrong value, especially if it is advanced far into the
future, this will cause mrtg to expire lots of supposedly old data from
the log files.
To prevent this, you can add a 'reasonability' check by specifying a
maximum age for log files. If a file seems to be older, mrtg will not
touch it but complain instead, giving you a chance to investigate the
cause.
Example:
MaxAge: 7200
The example above will make mrtg refuse to update log files older than
2 hours (7200 seconds).
WriteExpires
With this switch mrtg will generate .meta files for CERN and Apache
servers which contain Expiration tags for the html and gif files. The
*.meta files will be created in the same directory as the other files,
so you will have to set "MetaDir ." and "MetaFiles on" in your
apache.conf or .htaccess file for this to work
NOTE: If you are running Apache-1.2 or later, you can use the
mod_expire to achieve the same effect ... see the file htaccess.txt
Example:
WriteExpires: Yes
NoMib2
Normally we ask the SNMP device for 'sysUptime' and 'sysName'
properties. Some do not have these. If you want to avoid getting
complaints from mrtg about these missing properties, specify the nomib2
option.
An example of agents which do not implement base mib2 attributes are
Computer Associates - Unicenter TNG Agents. CA relies on using the
base OS SNMP agent in addition to its own agents to supplement the
management of a system.
Example:
NoMib2: Yes
SingleRequest
Some SNMP implementations can not deal with requests asking for
multiple snmp variables in one go. Set this in your cfg file to force
mrtg to only ask for one variable per request.
Examples
SingleRequest: Yes
SnmpOptions
Apart from the per target timeout options, you can also configure the
behaviour of the snmpget process on a more profound level. SnmpOptions
accepts a hash of options. The following options are currently
supported:
timeout => $default_timeout,
retries => $default_retries,
backoff => $default_backoff,
default_max_repetitions => $max_repetitions,
use_16bit_request_ids => 1,
lenient_source_port_matching => 0,
lenient_source_address_matching => 1
The values behind the options indicate the current default value. Note
that these settings OVERRIDE the per target timeout settings.
A per-target SnmpOptions[] keyword will override the global settings.
That keyword is primarily for SNMPv3.
The 16bit request ids are the only way to query the broken SNMP
implementation of SMC Barricade routers.
Example:
SnmpOptions: retries => 2, only_ip_address_matching => 0
Note that AS/400 snmp seems to be broken in a way which prevents mrtg
from working with it unless
SnmpOptions: lenient_source_port_matching => 1
is set.
IconDir
If you want to keep the mrtg icons in someplace other than the working
(or imagedir) directory, use the IconDir variable for defining the url
of the icons directory.
Example:
IconDir: /mrtgicons/
LoadMIBs
Load the MIB file(s) specified and make its OIDs available as symbolic
names. For better efficiancy, a cache of MIBs is maintained in the
WorkDir.
Example:
LoadMIBs: /dept/net/mibs/netapp.mib,/usr/local/lib/ft100m.mib
Language
Switch output format to the selected Language (Check the translate
directory to see which languages are supported at the moment. In this
directory you can also find instructions on how to create new
translations).
Currently the following laguages are supported:
big5 brazilian bulgarian catalan chinese croatian czech danish dutch
eucjp french galician gb gb2312 german greek hungarian icelandic
indonesia iso2022jp italian korean lithuanian malay norwegian polish
portuguese romanian russian russian1251 serbian slovak slovenian
spanish swedish turkish ukrainian
Example:
Language: danish
LogFormat
Setting LogFormat to 'rrdtool' in your mrtg.cfg file enables rrdtool
mode. In rrdtool mode, mrtg relies on rrdtool to do its logging. See
mrtg-rrd.
Example:
LogFormat: rrdtool
LibAdd
If you are using rrdtool mode and your rrdtool Perl module (RRDs.pm) is
not installed in a location where perl can find it on its own, you can
use LibAdd to supply an appropriate path.
Example:
LibAdd: /usr/local/rrdtool/lib/perl/
PathAdd
If the rrdtool executable can not be found in the normal "PATH", you
can use this keyword to add a suitable directory to your path.
Example:
PathAdd: /usr/local/rrdtool/bin/
RRDCached
If you are running RRDTool 1.4 or later with rrdcached, then you can
configure MRTG to take advantage of this for updates, either by using
the RRDCACHED_ADDRESS environment variable, or by setting the RRDCached
keyword in the configuration file. Note that, if both are set, the
configuration file keyword will take precedence.
Only UNIX domain sockets are fully supported prior to RRDTool v1.5, and
you should note that using RRDCached mode will disable all Threshold
checking normally done by MRTG. Appropriate warning messages will be
printed if necessary.
Examples:
RRDCached: unix:/var/tmp/rrdcached.sock
RRDCached: localhost:42217
RunAsDaemon
The RunAsDaemon keyword enables daemon mode operation. The purpose of
daemon mode is that MRTG is launched once and not repeatedly (as it is
with cron). This behavior saves computing resourses as loading and
parsing of configuration files happens only once on startup, and if the
configuration file is modified.
Using daemon mode MRTG itself is responible for timing the measurement
intervals. Therfore its important to set the Interval keyword to an
apropiate value.
Note that when using daemon mode MRTG should no longer be started from
cron as each new process runs forever. Instead MRTG should be started
from the command prompt or by a system startup script.
If you want mrtg to run under a particular user and group (it is not
recomended to run MRTG as root) then you can use the --user=user_name
and --group=group_name options on the mrtg commandline.
mrtg --user=mrtg_user --group=mrtg_group mrtg.cfg
Also note that in daemon mode restarting the process is required in
order to activate changes in the config file.
Under UNIX, the Daemon switch causes mrtg to fork into background after
checking its config file. On Windows NT the MRTG process will detach
from the console, but because the NT/2000 shell waits for its children
you have to use this special start sequence when you launch the
program:
start /b perl mrtg mrtg.cfg
You may have to add path information equal to what you add when you run
mrtg from the commandline.
Example
RunAsDaemon: Yes
Interval: 5
This makes MRTG run as a daemon beginning data collection every 5
minutes
If you are daemontools and still want to run mrtg as a daemon you can
additionally specify
NoDetach: Yes
this will make mrtg run but without detaching it from the terminal.
If the modification date on the configuration file changes during
operation, then MRTG will re-read the configuration on the next polling
cycle. Note that sub-files which are included from the main
configuration do not have their modification times monitored, only the
top-level file is so checked.
ConversionCode
Some devices may produce non-numeric values that would nevertheless be
useful to graph with MRTG if those values could be converted to
numbers. The ConversionCode keyword specifies the path to a file
containing Perl code to perform such conversions. The code in this file
must consist of one or more Perl subroutines. Each subroutine must
accept a single string argument and return a single numeric value. When
RRDtool is in use, a decimal value may be returned. When the name of
one of these subroutines is specified in a target definition (see
below), MRTG calls it twice for that target, once to convert the the
input value being monitored and a second time to convert the output
value. The subroutine must return an undefined value if the conversion
fails. In case of failure, a warning may be posted to the MRTG log file
using Perl's warn function. MRTG imports the subroutines into a
separate name space (package MRTGConversion), so the user need not
worry about pollution of MRTG's global name space. MRTG automatically
prepends this package declaration to the user-supplied code.
Example: Suppose a particular OID returns a character string whose
length is proportional to the value to be monitored. To convert this
string to a number that can be graphed by MRTG, create a file
arbitrarily named "MyConversions.pl" containing the following code:
# Return the length of the string argument
sub Length2Int {
my $value = shift;
return length( $value );
}
Then include the following global keyword in the MRTG configuration
file (assuming that the conversion code file is saved in the mrtg/bin
directory along with mrtg itself):
ConversionCode: MyConversions.pl
This will cause MRTG to include the definition of the subroutine
Length2Int in its execution environment. Length2Int can then be invoked
on any target by appending "|Length2Int" to the target definition as
follows:
Target[myrouter]: 1.3.6.1.4.1.999.1&1.3.6.1.4.1.999.1:public@mydevice|Length2Int
See "Extended Host Name Syntax" below for complete target definition
syntax information.
PER TARGET CONFIGURATION
Each monitoring target must be identified by a unique name. This name
must be appended to each parameter belonging to the same target. The
name will also be used for naming the generated webpages, logfiles and
images for this target.
Target
With the Target keyword you tell mrtg what it should monitor. The
Target keyword takes arguments in a wide range of formats:
Basic
The most basic format is "port:community@router" This will generate
a traffic graph for the interface 'port' of the host 'router' (dns
name or IP address) and it will use the community 'community' (snmp
password) for the snmp query.
Example:
Target[myrouter]: 2:public@wellfleet-fddi.domain
If your community contains a "@" or a " " these characters must be
escaped with a "\".
Target[bla]: 2:stu\ pi\@d@router
SNMPv2c
If you have a fast router you might want to try to poll the ifHC*
counters. This feature gets activated by switching to SNMPv2c.
Unfortunately not all devices support SNMPv2c yet. If it works,
this will prevent your counters from wraping within the 5 minute
polling interval, since we now use 64 bit instead of the normal 32
bit.
Example:
Target[myrouter]: 2:public@router1:::::2
SNMPv3
As an alternative to SNMPv2c, SNMPv3 provides access to the ifHC*
counters, along with encryption. Not all devices support SNMPv3,
and you will also need the perl Net::SNMP library in order to use
it. It is recommended that cfgmaker be used to generate
configurations involving SNMPv3, as it will check if the Net::SNMP
library is loadable, and will switch to SNMPv2c if v3 is
unavailable.
SNMP v3 requires additional authentication parameters, passed using
the SnmpOptions[] per-target keyword.
Example:
Target[myrouter]: 2:router1:::::3
SnmpOptions[myrouter]: username=>'user1'
noHC
Not all routers that support SNMPv2 or SNMPv3 provide the ifHC*
counters on every interface. The noHC[] per-target keyword signals
that the low-speed counters ifInOctets and ifOutOctets should be
queried instead. cfgmaker will automatically insert this tag if
SNMPv2 or SNMPv3 is specified but the ifHC* counters are
unavailable.
Example:
Target[myrouter]: #Bri0:router1:::::3
SnmpOptions[myrouter]: username=>'user1'
noHC[myrouter]: yes
Reversing
Sometimes you are sitting on the wrong side of the link, and you
would like to have mrtg report Incoming traffic as Outgoing and
vice versa. This can be achieved by adding the '-' sign in front of
the "Target" description. It flips the incoming and outgoing
traffic rates.
Example:
Target[ezci]: -1:public@ezci-ether.domain
Explicit OIDs
You can also explicitly define which OID to query by using the
following syntax 'OID_1&OID_2:community@router' The following
example will retrieve error counts for input and output on
interface 1. MRTG needs to graph two variables, so you need to
specify two OID's such as temperature and humidity or error input
and error output.
Example:
Target[myrouter]: 1.3.6.1.2.1.2.2.1.14.1&1.3.6.1.2.1.2.2.1.20.1:public@myrouter
MIB Variables
MRTG knows a number of symbolic SNMP variable names. See the file
mibhelp.txt for a list of known names. One example are the
ifInErrors and ifOutErrors. This means you can specify the above
as:
Example:
Target[myrouter]: ifInErrors.1&ifOutErrors.1:public@myrouter
SnmpWalk
It may be that you want to monitor an snmp object that is only
reachable by 'walking'. You can get mrtg to walk by prepending the
OID with the string WaLK or if you want a particular entry from the
table returned by the walk you can use WaLKx where x is a number
starting from 0 (!).
Example:
Target[myrouter]: WaLKstrangeOid.1&WaLKstrangeOid.2:public@myrouter
Target[myrouter]: WaLK3strangeOid.1&WaLK4strangeOid.2:public@myrouter
SnmpGetNext
A special case of an snmp object that is only reachable by
'walking' occurs when a single snmpgetnext will return the correct
value, but snmpwalk fails. This may occur with snmp V2 or V3, as
the snmpgetbulk method is used in these versions. You can get mrtg
to use getnext instead of getbulk by prepending the OID with the
string GeTNEXT.
Example:
Target[myrouter]: GeTNEXTstrangeOid&GeTNEXTstrangeOid:public@myrouter
Counted SNMP Walk
In other situations, an snmpwalk is needed to count rows, but the
actual data is uninteresting. For example, counting the number of
mac-addresses in a CAM table, or the number of simultaneous dialup
sessions. You can get MRTG to count the number of instances by
prepending the OID with the string CnTWaLK. The following will
retrieve the number of simultaneous VOIP calls on some routers:
Example:
Target[myrouter]: CnTWaLK1.3.6.1.4.1.9.10.55.1.1.1.1.3&CnTWaLK1.3.6.1.4.1.9.10.55.1.1.1.1.3:public@myrouter
Interface by IP
Sometimes SNMP interface index can change, like when new interfaces
are added or removed. This can cause all Target entries in your
config file to become offset, causing MRTG to graphs wrong
instances etc. MRTG supports IP address instead of ifindex in
target definition. Then MRTG will query snmp device and try to map
IP address to the current ifindex. You can use IP addresses in
every type of target definition by adding IP address of the
numbered interface after OID and separation char '/'.
Make sure that the given IP address is used on your same target
router, especially when graphing two different OIDs and/or
interface split by '&' delimiter.
You can tell cfgmaker to generate such references with the option
--ifref=ip.
Example:
Target[myrouter]: /1.2.3.4:public@wellfleet-fddi.domain
Target[ezci]: -/1.2.3.4:public@ezci-ether.domain
Target[myrouter]: ifInErrors/1.2.3.4&ifOutErrors/1.2.3.4:public@myrouter
Interface by Description
If you can not use IP addresses you might want to use the interface
names. This works similar to the IP address aproach except that the
prefix to use is a \ instead of a /
You can tell cfgmaker to generate such references with the option
--ifref=descr.
Example:
Target[myrouter]: \My-Interface2:public@wellfleet-fddi.domain
Target[ezci]: -\My-Interface2:public@ezci-ether.domain
Target[myrouter]: ifInErrors\My-If2&ifOutErrors\My-If3:public@myrouter
If your description contains a "&", a ":", a "@" or a " " you can
include them but you must escape with a backlash:
Target[myrouter]: \fun\:\ ney\&ddd:public@hello.router
Interface by Name
This is the only sensible way to reference the interfaces of your
switches.
You can tell cfgmaker to generate such references with the option
--ifref=name.
Example:
Target[myrouter]: #2/11:public@wellfleet-fddi.domain
Target[ezci]: -#2/11:public@ezci-ether.domain
Target[myrouter]: ifInErrors#3/7&ifOutErrors#3/7:public@myrouter
If your description contains a "&", a ":", a "@" or a " " you can
include them but you must escape with a backlash:
Target[myrouter]: #\:\ fun:public@hello.router
Note that the # sign will be interpreted as a comment character if
it is the first non white-space character on the line.
Interface by Ethernet Address
When the SNMP interface index changes, you can key that interface
by its 'Physical Address', sometimes called a 'hard address', which
is the SNMP variable 'ifPhysAddress'. Internally, MRTG matches the
Physical Address from the *.cfg file to its current index, and then
uses that index for the rest of the session.
You can use the Physical Address in every type of target definition
by adding the Physical Address after the OID and the separation
char '!' (analogous to the IP address option). The Physical
address is specified as '-' delimited octets, such as
"0a-0-f1-5-23-18" (omit the double quotes). Note that some routers
use the same Hardware Ethernet Address for all of their Interfaces
which prevents unique interface identification. Mrtg will notice
such problems and alert you.
You can tell cfgmaker to generate configuration files with hardware
ethernet address references by using the option --ifref=eth.
Example:
Target[myrouter]: !0a-0b-0c-0d:public@wellfleet-fddi.domain
Target[ezci]: -!0-f-bb-05-71-22:public@ezci-ether.domain
Target[myrouter]: 1.3.6.1.2.1.2.2.1.14!0a-00-10-23-44-51& *BREAK*
1.3.6.1.2.1.2.2.1.14!0a-00-10-23-44-51:public@myrouter
Target[myrouter]: ifInErrors!0a-00-10-23-44-51& *BREAK*
ifOutErrors!0a-00-10-23-44-51:public@myrouter
Join the lines at *BREAK* ...
Interface by Type
It seems that there are devices that try to defy all monitoring
efforts: the interesting interfaces have neither ifName nor a
constant ifDescr not to mention a persistent ifIndex. The only way
to get a constant mapping is by looking at the interface type,
because the interface you are interested in is unique in the device
you are looking at ...
You can tell cfgmaker to generate such references with the option
--ifref=type.
Example:
Target[myrouter]: %13:public@wellfleet-fddi.domain
Target[ezci]: -%13:public@ezci-ether.domain
Target[myrouter]: ifInErrors%13&ifOutErrors%14:public@myrouter
Extended positioning of ifIndex
There are OIDs that contain the interface index at some inner
position within the OID. To use the above mentioned Interface by
IP/Description/Name/Type methods in the target definition the
keyword 'IndexPOS' can be used to indicate the position of ifIndex.
If 'IndexPOS' is not used the ifIndex will be appended at the end
of the OID.
Example:
Target[myrouter]: OID.IndexPOS.1/1.2.3.4&OID.IndexPOS.1/1.2.3.4:public@myrouter
Replace OID by your numeric OID.
Extended Host Name Syntax
In all places where ``community@router'' is accepted, you can add
additional parameters for the SNMP communication using colon-
separated suffixes. You can also append a pipe symbol ( | ) and the
name of a numeric conversion subroutine as described under the
global keyword "ConversionCode" above. The full syntax is as
follows:
community@router[:[port][:[timeout][:[retries][:[backoff][:[version]][|name]]]]]
where the meaning of each parameter is as follows:
port
the UDP port under which to contact the SNMP agent (default:
161)
The complete syntax of the port parameter is
remote_port[!local_address[!local_port]]
Some machines have additional security features that only allow
SNMP queries to come from certain IP addresses. If the host
doing the query has multiple interface, it may be necessary to
specify the interface the query should come from.
The port parameter allows the specification of the port of the
machine being queried. In addition, the IP address (or
hostname) and port of the machine doing the query may be
specified.
Examples:
somehost
somehost:161
somehost:161!192.168.2.4!4000 use 192.168.2.4 and port 4000 as source
somehost:!192.168.2.4 use 192.168.2.4 as source
somehost:!!4000 use port 4000 as source
timeout
initial timeout for SNMP queries, in seconds (default: 2.0)
retries
number of times a timed-out request will be retried (default:
5)
backoff
factor by which the timeout is multiplied on every retry
(default: 1.0).
version
for SNMP version. If you have a fast router you might want to
put a '2' here. For authenticated or encrypted SNMP, you can
try to put a '3' here. This will make mrtg try to poll the 64
bit counters and thus prevent excessive counter wrapping. Not
all routers support this though. SNMP v3 requires additional
setup, see SnmpOptions[] for full details.
Example:
3:public@router1:::::2
name
the name of the subroutine that MRTG will call to convert the
input and output values to integers. See the complete example
under the global keyword "ConversionCode" above.
Example:
1.3.6.1.4.1.999.1&1.3.6.1.4.1.999.2:public@mydevice:161::::2|Length2Int
This would retrieve values from the OID 1.3.6.1.4.1.999.1 for
input and .2 for output on mydevice using UDP port 161 and SNMP
version 2, and would execute the user-defined numeric
conversion subroutine Length2Int to convert those values to
integers.
A value that equals the default value can be omitted. Trailing
colons can be omitted, too. The pipe symbol followed by the name
parameter, if present, must come at the end. There must be no
spaces around the colons or pipe symbol.
Example:
Target[ezci]: 1:public@ezci-ether.domain:9161::4
This would refer to the input/output octet counters for the
interface with ifIndex 1 on ezci-ether.domain, as known by the SNMP
agent listening on UDP port 9161. The standard initial timeout
(2.0 seconds) is used, but the number of retries is set to four.
The backoff value is the default.
Numeric IPv6 addresses
If IPv6 is enabled you may also specify a target using its IPv6
address. To avoid ambiguity with the port number, numeric IPv6
addresses must be placed in square brackets.
Example:
Target[IPv6test]: 2:public@[2001:760:4::]:6161::4
External Monitoring Scripts
If you want to monitor something which does not provide data via
snmp you can use some external program to do the data gathering.
The external command must return 4 lines of output:
Line 1
current state of the first variable, normally 'incoming bytes
count'
Line 2
current state of the second variable, normally 'outgoing bytes
count'
Line 3
string (in any human readable format), telling the uptime of
the target.
Line 4
string, telling the name of the target.
Depending on the type of data your script returns you might want to
use the 'gauge' or 'absolute' arguments for the Options keyword.
Example:
Target[myrouter]: `/usr/local/bin/df2mrtg /dev/dsk/c0t2d0s0`
Note the use of the backticks (`), not apostrophes (') around the
command.
If you want to use a backtick in the command name this can be done
but you must escape it with a backslash ...
If your script does not have any data to return but does not want
mrtg to complain about invalid data, it can return 'UNKNOWN'
instead of a number. Note though that only rrdtool is realy
equipped to handle unknown data well.
Multi Target Syntax
You can also combine several target definitions in a mathematical
expression. Any syntactically correct expression that the Perl
interpreter can evaluate to will work. An expression could be used,
for example, to aggregate both B channels in an ISDN connection or
to calculate the percentage hard disk utilization of a server from
the absolute used space and total capacity.
Examples:
Target[myrouter]: 2:public@wellfleetA + 1:public@wellfleetA
Target[myrouter]: .1.3.6.1.4.1.999.1&.1.3.6.1.4.1.999.2:public@mydevice /
.1.3.6.1.4.1.999.3&.1.3.6.1.4.1.999.4:public@mydevice * 100
Note that whitespace must surround each target definition in the
expression. Target definitions themselves must not contain
whitespace, except in interface descriptions and interface names,
where each whitespace character is escaped by a backslash.
MRTG automatically rounds the result of the expression to an
integer unless RRDTool logging is in use and the gauge option is in
effect for the target. Internally MRTG uses Perl's Math::BigFloat
package to calculate the result of the expression with 40 digits of
precision. Even in extreme cases, where, for example, you take the
difference of two 64-bit integers, the result of the expression
should be accurate.
SNMP Request Optimization
MRTG is designed to economize on its SNMP requests. Where a target
definition appears more than once in the configuration file, MRTG
requests the data from the device only once per round of data
collection and uses the collected data for each instance of a
particular target. Recognition of two target definitions as being
identical is based on a simple string match rather than any kind of
deeper semantic analysis.
Example:
Target[Targ1]: 1:public@CiscoA
Target[Targ2]: 2:public@CiscoA
Target[Targ3]: 1:public@CiscoA + 2:public@CiscoA
Target[Targ4]: 1:public@CISCOA
This results in a total of three SNMP requests. Data for
1:public@CiscoA and 2:public@CiscoA are requested only once each,
and used for Targ1, Targ2, and Targ3. Targ4 causes another SNMP
request for 1:public@CISCOA, which is not recognized as being
identical to 1:public@CiscoA.
MaxBytes
The maximum value either of the two variables monitored are allowed to
reach. For monitoring router traffic this is normally the bytes per
second this interface port can carry.
If a number higher than MaxBytes is returned, it is ignored. Also read
the section on AbsMax for further info. The MaxBytes value is also
used in calculating the Y range for unscaled graphs (see the section on
Unscaled).
Since most links are rated in bits per second, you need to divide their
maximum bandwidth (in bits) by eight (8) in order to get bytes per
second. This is very important to make your unscaled graphs display
realistic information. T1 = 193000, 56K = 7000, 10 MB Ethernet =
1250000, 100 MB Ethernet = 12500000. The MaxBytes value will be used by
mrtg to decide whether it got a valid response from the router.
If you need two different MaxBytes values for the two monitored
variables, you can use MaxBytes1 and MaxBytes2 instead of MaxBytes.
Example:
MaxBytes[myrouter]: 1250000
Title
Title for the HTML page which gets generated for the graph.
Example:
Title[myrouter]: Traffic Analysis for Our Nice Company
OPTIONAL PER TARGET KEYWORDS
PageTop
Things to add to the top of the generated HTML page. Note that you can
have several lines of text as long as the first column is empty.
Note that the continuation lines will all end up on the same line in
the html page. If you want linebreaks in the generated html use the
'\n' sequence.
Example:
PageTop[myrouter]: <H1>Traffic Analysis for ETZ C95.1</H1>
Our Campus Backbone runs over an FDDI line\n
with a maximum transfer rate of 12.5 megabytes per
Second.
RouterUptime
In cases where you calculate the used bandwidth from several interfaces
you normally don't get the router uptime and router name displayed on
the web page.
If these interfaces are on the same router and the uptime and name
should be displayed you have to specify its community and address again
with the RouterUptime keyword.
If you want to use a special OID for querying the router uptime, use
prepend the oid.
Example:
Target[kacisco.comp.edu]: 1:public@194.64.66.250 + 2:public@194.64.66.250
RouterUptime[kacisco.comp.edu]: public@194.64.66.250
RouterUptime[kacisco.comp.edu]: hrSystemUptime.0:public@194.64.66.250
RouterName
If the default name of the router is incorrect/uninformative, you can
use RouterName to specify a different OID on either the same or a
different host.
A practical example: sysName on BayTech DS72 units always display
"ds72", no matter what you set the Unit ID to be. Instead, the Unit ID
is stored at 1.3.6.1.4.1.4779.1.1.3.0, so we can have MRTG display this
instead of sysName.
Example:
RouterName[kacisco.comp.edu]: 1.3.6.1.4.1.4779.1.1.3.0
A different OID on a different host can also be specified:
RouterName[kacisco.comp.edu]: 1.3.6.1.4.1.4779.1.1.3.0:public@194.64.66.251
MaxBytes1
Same as MaxBytes, for variable 1.
MaxBytes2
Same as MaxBytes, for variable 2.
IPv4Only
Many IPv6 routers do not currently support SNMP over IPv6 and must be
monitored using IPv4. The IPv4Only option forces mrtg to use IPv4 when
communicating with the target, even if IPv6 is enabled. This is useful
if the target is a hostname with both IPv4 and IPv6 addresses; without
the IPv4Only keyword, monitoring such a router will not work if IPv6 is
enabled.
If set to no (the default), mrtg will use IPv6 unless the target has no
IPv6 addresses, in which case it will use IPv4. If set to yes, mrtg
will only use IPv4.
Note that if this option is set to yes and the target does not have an
IPv4 address, communication with the target will fail.
This option has no effect if IPv6 is not enabled.
Example:
Target[v4onlyrouter_1]: 1:public@v4onlyrouter
IPv4Only[v4onlyrouter_1]: Yes
SnmpOptions (V3)
SNMPv3 requires a fairly rich set of options. This per-target keyword
allows access to the User Security Model of SNMPv3. Options are listed
in the same syntax as a perl hash.
Security Modes
SNMPv3 has three security modes, defined on the device being polled.
For example, on Cisco routers the security mode is defined by the snmp-
server group global configuration command.
NoAuthNoPriv
Neither Authentication nor Privacy is defined. Only the Username
option is specified for this mode.
Example:
SnmpOptions[myrouter]: username=>'user1'
AuthNoPriv
Uses a Username and a password. The password can be hashed using
the snmpkey application, or passed in plain text along with the
ContextEngineID
Example:
SnmpOptions[myrouter]: username=>'user1',authpassword=>'example',
contextengineid=>'80000001110000004000000'
Priv
Both Authentication and Privacy is defined. The default privacy
protocol is des.
Example:
SnmpOptions[myrouter]:
authkey=>'0x1e93ab5a396e2af234c8920e61cfe2028072c0e2',
authprotocol=>'sha',privprotocol=>'des',username=>'user1',
privkey=>'0x498d74940c5872ed387201d74b9b25e2'
snmp options
The following option keywords are recognized:
username
The user associated with the User Security Model
contextname
An SNMP agent can define multiple contexts. This keyword allows
them to be polled.
contextengineid
A unique 24-byte string identifying the snmp-agent.
authpassword
The plaintext password for a user in either AuthNoPriv or Priv
mode.
authkey
A md5 or sha hash of the plain-text password, along with the
engineid. Use the snmpkey commandline program to generate this
hash, or use Net::SNMP::Security::USM in a script.
authprotocol {sha|md5}
The hashing algorithm defined on the SNMP client. Defaults to md5.
privpassword
A plaintext pre-shared key for encrypting snmp packets in Priv
mode.
privkey
A hash of the plain-text pre-shared key, along with the engineid.
Use the snmpkey commandline program to generate this hash, or use
Net::SNMP::Security::USM in a script.
privprotocol {des|3desede|aescfb128|aescfb192|aescfb256}
Specifies the encryption method defined on the snmp agent. The
default is des.
PageFoot
Things to add to the bottom of the generated HTML page. Note that you
can have several lines of text as long as the first column is empty.
Note that the continuation lines will all end up on the same line in
the html page. If you want linebreaks in the generated html use the
'\n' sequence.
The material will be added just before the </BODY> tag:
Example:
PageFoot[myrouter]: Contact <A HREF="mailto:peter@x.yz">Peter</A>
if you have questions regarding this page
AddHead
Use this tag like the PageTop header, but its contents will be added
between </TITLE> and </HEAD>.
Example:
AddHead[myrouter]: <link rev="made" href="mailto:mrtg@blabla.edu">
BodyTag
BodyTag lets you supply your very own <body ...> tag for the generated
webpages.
Example:
BodyTag[myrouter]: <BODY LEFTMARGIN="1" TOPMARGIN="1"
BACKGROUND="/stats/images/bg.neo2.gif">
AbsMax
If you are monitoring a link which can handle more traffic than the
MaxBytes value. Eg, a line which uses compression or some frame relay
link, you can use the AbsMax keyword to give the absolute maximum value
ever to be reached. We need to know this in order to sort out
unrealistic values returned by the routers. If you do not set AbsMax,
rateup will ignore values higher than MaxBytes.
Example:
AbsMax[myrouter]: 2500000
Unscaled
By default each graph is scaled vertically to make the actual data
visible even when it is much lower than MaxBytes. With the Unscaled
variable you can suppress this. It's argument is a string, containing
one letter for each graph you don't want to be scaled: d=day w=week
m=month y=year. There is also a special case to unset the variable
completely: n=none. This could be useful in the event you need to
override a global configuration. In the example scaling for the yearly
and the monthly graph are suppressed.
Example:
Unscaled[myrouter]: ym
WithPeak
By default the graphs only contain the average values of the monitored
variables - normally the transfer rates for incoming and outgoing
traffic. The following option instructs mrtg to display the peak 5
minute values in the [w]eekly, [m]onthly and [y]early graph. In the
example we define the monthly and the yearly graph to contain peak as
well as average values.
Examples:
WithPeak[myrouter]: ym
Suppress
By default mrtg produces 4 graphs. With this option you can suppress
the generation of selected graphs. The option value syntax is
analogous to the above two options. In this example we suppress the
yearly graph as it is quite empty in the beginning.
Example:
Suppress[myrouter]: y
Extension
By default, mrtg creates .html files. Use this option to tell mrtg to
use a different extension. For example you could set the extension to
php3, then you will be able to enclose PHP tags into the output (useful
for getting a router name out of a database).
Example:
Extension[myrouter]: phtml
Directory
By default, mrtg puts all the files that it generates for each target
(the GIFs, the HTML page, the log file, etc.) in WorkDir.
If the Directory option is specified, the files are instead put into a
directory under WorkDir or Log-, Image- and HtmlDir). (For example the
Directory option below would cause all the files for a target myrouter
to be put into directory /usr/tardis/pub/www/stats/mrtg/myrouter/ .)
The directory must already exist; mrtg will not create it.
Example:
WorkDir: /usr/tardis/pub/www/stats/mrtg
Directory[myrouter]: myrouter
NOTE: the Directory option must always be 'relative' or bad things will
happen.
Clonedirectory
If the Directory option is specified, the Clonedirectory option will
copy all the contents of Directory to the Clonedirectory.
Example:
WorkDir: /usr/tardis/pub/www/stats/mrtg
Directory[myrouter]: myrouter
Clonedirectory[myrouter]: myclonedirectory
Optionally the target name can be changed in the cloning process.
Example:
WorkDir: /usr/tardis/pub/www/stats/mrtg
Directory[myrouter]: myrouter
Clonedirectory[myrouter]: myclonedirectory mynewtarget
NOTE1: The clone directory must already exist; mrtg will not create it.
NOTE2: The Clonedirectory option must also always be 'relative' or bad
things will happen.
NOTE3: This requires the File::Copy module
XSize and YSize
By default mrtgs graphs are 100 by 400 pixels wide (plus some more for
the labels. In the example we get almost square graphs ...
Note: XSize must be between 20 and 600; YSize must be larger than 20
Example:
XSize[myrouter]: 300
YSize[myrouter]: 300
XZoom and YZoom
If you want your graphs to have larger pixels, you can "Zoom" them.
Example:
XZoom[myrouter]: 2.0
YZoom[myrouter]: 2.0
XScale and YScale
If you want your graphs to be actually scaled use XScale and YScale.
(Beware: while this works, the results look ugly (to be frank) so if
someone wants to fix this: patches are welcome.
Example:
XScale[myrouter]: 1.5
YScale[myrouter]: 1.5
YTics and YTicsFactor
If you want to show more than 4 lines per graph, use YTics. If you
want to scale the value used for the YLegend of these tics, use
YTicsFactor. The default value for YTics is 4 and the default value
for YTicsFactor is 1.0 .
Example:
Suppose you get values ranging from 0 to 700. You want to plot 7 lines
and want to show 0, 1, 2, 3, 4, 5, 6, 7 instead of 0, 100, 200, 300,
400, 500, 600, 700. You should write then:
YTics[myrouter]: 7
YTicsFactor[myrouter]: 0.01
Factor
If you want to multiply all numbers shown below the graph with a
constant factor, use this directive to define it ..
Example:
Factor[as400]: 4096
Step
Change the default step from 5 * 60 seconds to something else (I have
not tested this much ...)
Example:
Step[myrouter]: 60
PNGTitle
When using rateup for graph generation, this will print the given title
in the graph it generates.
Example:
PNGTitle[myrouter]: WAN Link UK-US
Options
The Options Keyword allows you to set some boolean switches:
growright
The graph grows to the left by default. This option flips the
direction of growth causing the current time to be at the right
edge of the graph and the history values to the left of it.
bits
All the monitored variable values are multiplied by 8 (i.e. shown
in bits instead of bytes) ... looks much more impressive :-) It
also affects the 'factory default' labeling and units for the given
target.
perminute
All the monitored variable values are multiplied by 60 (i.e. shown
in units per minute instead of units per second) in case of small
values more accurate graphs are displayed. It also affects the
'factory default' labeling and units for the given target.
perhour
All the monitored variable values are multiplied by 3600 (i.e.
shown in units per hour instead of units per second) in case of
small values more accurate graphs are displayed. It also affects
the 'factory default' labeling and units for the given target.
noinfo
Suppress the information about uptime and device name in the
generated webpage.
nopercent
Don't print usage percentages.
transparent
Make the background of the generated gifs transparent.
integer
Print summary lines below graph as integers without commas.
dorelpercent
The relative percentage of IN-traffic to OUT-traffic is calculated
and displayed in the graph as an additional line. Note: Only a
fixed scale is available (from 0 to 100%). Therefore if IN-traffic
is greater than OUT-traffic then 100% is displayed. If you suspect
that your IN-traffic is not always less than or equal to your OUT-
traffic you are urged to not use this options. Note: If you use
this option in combination with the Colours options, a fifth
colour-name colour-value pair is required there.
avgpeak
There are some ISPs who use the average Peak values to bill their
customers. Using this option MRTG displays these values for each
graph. The value is built by averaging the max 5 minute traffic
average for each 'step' shown in the graph. For the Weekly graph
this means that it builds the average of all 2 hour intervals 5
minute peak values. (Confused? Thought so!)
gauge
Treat the values gathered from target as 'current status'
measurements and not as ever incrementing counters. This would be
useful to monitor things like disk space, processor load,
temperature, and the like ...
In the absence of 'gauge' or 'absolute' options, MRTG treats
variables as a counters and calculates the difference between the
current and the previous value and divides that by the elapsed time
between the last two readings to get the value to be plotted.
absolute
This is for counter type data sources which reset their value when
they are read. This means that rateup does not have to build the
difference between the current and the last value read from the
data source. The value obtained is still divided by the elapsed
time between the current and the last reading, which makes it
different from the 'gauge' option. Useful for external data
gatherers.
derive
If you are using rrdtool as logger/grapher you can use a third type
of data source. Derive is like counter, except that it is not
required to go UP all the time. It is useful for situations where
the change of some value should be graphed.
unknaszero
Log unknown data as zero instead of the default behaviour of
repeating the last value seen. Be careful with this, often a flat
line in the graph is much more obvious than a line at 0.
withzeroes
Normally we ignore all values which are zero when calculating the
average transfer rate on a line. If this is not desirable use this
option.
noborder
If you are using rateup to log data, MRTG will create the graph
images. Normally these images have a shaded border around them. If
you do not want the border to be drawn, enable this option. This
option has no effect if you are not using rateup.
noarrow
As with the option above, this effects rateup graph generation
only. Normally rateup will generate graphs with a small arrow
showing the direction of the data. If you do not want this arrow to
be drawn, enable this option. This option has no effect if you are
not using rateup.
noi When using rateup for graph generation, you can use this option to
stop rateup drawing a graph for the 'I' or first variable. This
also removes entries for this variable in the HTML page MRTG
generates, and will remove the peaks for this variable if they are
enabled. This allows you to hide this data, or can be very useful
if you are only graphing one line of data rather than two. This
option is not destructive - any data received for the the variable
continued to be logged, it just isn't shown.
noo Same as above, except relating to the 'O' or second variable.
nobanner
When using rateup for graph generation, this option disables MRTG
adding the MRTG banner to the HTML pages it generates.
nolegend
When using rateup for graph generation, this option will stop MRTG
from creating a legend at the bottom of the HTML pages it
generates.
printrouter
When using rateup for graph generation, this option will print the
router name in the graph it generates. This option is overridden
by the value of PNGTitle if one is given
pngdate
When using rateup for graph generation, this option will print a
timestamp in the graph it generates, including a timezone if one is
specified by the 'Timezone' parameter. This is aequivalent to
setting TimeStrPost[x]: RU
logscale
The logscale option causes rateup to display the data with the Y
axis scaled logarithmically. Doing so allows the normal traffic to
occupy the majority of the vertical range, while still showing any
spikes at their full height.
logscale displays all the available data and will always produce
well-behaved graphs. People often consider a logarithmically
scaled graph counterintuitive, however, and thus hard to interpret.
expscale
The expscale option causes rateup to display the data with the Y
axis scaled exponentially. Doing so emphasizes small changes at
the top of the scale; this can be useful when graphing values that
fluctuate by a small amount near the top of the scale, such as line
voltage.
expscale is essentially the inverse of logscale.
secondmean
The secondmean option sets the maximum value on the graph to the
mean of the data greater than the mean of all data. This produces
a graph that focuses more on the typical data, while clipping large
peaks.
Using secondmean will give a more intutive linearly scaled graph,
but can result in a uselessly high or low scale in some rare
situations (specifically, when the data includes a large portion of
values far from the actual mean)
If a target includes both logscale and secondmean in the options,
the secondmean takes precedence.
Example:
Options[myrouter]: growright, bits
kilo
Use this option to change the multiplier value for building prefixes.
Defaultvalue is 1000. This tag is for the special case that 1kB =
1024B, 1MB = 1024kB and so far.
Example:
kilo[myrouter]: 1024
kMG
Change the default multiplier prefixes (,k,M,G,T,P). In the tag
ShortLegend define only the basic units. Format: Comma separated list
of prefixed. Two consecutive commas or a comma at start or end of the
line gives no prefix on this item. If you do not want prefixes, just
put two consecutive commas. If you want to skip a magnitude select '-'
as value.
Example: velocity in nm/s (nanometers per second) displayed in nm/h.
ShortLegend[myrouter]: m/h
kMG[myrouter]: n,u,m,,k,M,G,T,P
options[myrouter]: perhour
Colours
The Colours tag allows you to override the default colour scheme.
Note: All 4 of the required colours must be specified here. The colour
name ('Colourx' below) is the legend name displayed, while the RGB
value is the real colour used for the display, both on the graph and in
the html doc.
Format is: Col1#RRGGBB,Col2#RRGGBB,Col3#RRGGBB,Col4#RRGGBB
Important: If you use the dorelpercent options tag a fifth colour name
colour value pair is required:
Col1#RRGGBB,Col2#RRGGBB,Col3#RRGGBB,Col4#RRGGBB,Col5#RRGGBB
Colour1
First variable (normally Input) on default graph.
Colour2
Second variable (normally Output) on default graph.
Colour3
Max first variable (input).
Colour4
Max second variable (output).
RRGGBB
2 digit hex values for Red, Green and Blue.
Example:
Colours[myrouter]: GREEN#00eb0c,BLUE#1000ff,DARK GREEN#006600,VIOLET#ff00ff
Background
With the Background tag you can configure the background colour of the
generated HTML page.
Example:
Background[myrouter]: #a0a0a0a
YLegend, ShortLegend, Legend[1234]
The following keywords allow you to override the text displayed for the
various legends of the graph and in the HTML document:
YLegend
The Y-axis label of the graph. Note that a text which is too long
to fit in the graph will be silently ignored.
ShortLegend
The units string (default 'b/s') used for Max, Average and Current
Legend[1234IO]
The strings for the colour legend.
Example:
YLegend[myrouter]: Bits per Second
ShortLegend[myrouter]: b/s
Legend1[myrouter]: Incoming Traffic in Bits per Second
Legend2[myrouter]: Outgoing Traffic in Bits per Second
Legend3[myrouter]: Maximal 5 Minute Incoming Traffic
Legend4[myrouter]: Maximal 5 Minute Outgoing Traffic
LegendI[myrouter]: In:
LegendO[myrouter]: Out:
Note, if LegendI or LegendO are set to an empty string with
LegendO[myrouter]:
The corresponding line below the graph will not be printed at all.
Timezone
If you live in an international world, you might want to generate the
graphs in different timezones. This is set in the TZ variable. Under
certain operating systems like Solaris, this will provoke the localtime
call to give the time in the selected timezone.
Example:
Timezone[myrouter]: Japan
The Timezone is the standard timezone of your system, ie Japan,
Hongkong, GMT, GMT+1 etc etc.
Weekformat
By default, mrtg (actually rateup) uses the strftime(3) '%V' option to
format week numbers in the monthly graphs. The exact semantics of this
format option vary between systems. If you find that the week numbers
are wrong, and your system's strftime(3) routine supports it, you can
try another format option. The POSIX '%V' option correspond to the
widely used ISO 8601 week numbering standard. The week format
character should be specified as a single letter; either W, V, or U.
The UNIX version of rateup uses the libc implementation of strftime.
On Windows, the native strftime implementation does not know about %V.
So there we use a different implementation of strftime that does
support %V.
Example:
Weekformat[myrouter]: W
RRDRowCount
This affects the creation of new rrd files. By default rrds are created
to hold about 1 day's worth of high resolution data. (plus 1 week of 30
minute data, 2 months of 2 hour data and 2 years of 1 day data). With
this Keyword you can change the number of base interval entries
configured for new rrds as they get created. Note that you must take
the interval time into account.
Example:
RRDRowCount[myrouter]: 1600
RRDRowCount30m
As per RRDRowCount, but for the RRA's -typically- used for 30 minute
data. Even so, you must still take the base interval into account.
Leaving out this keyword will force the old default of 800 rows.
Example:
RRDRowCount30m[myrouter]: 800
RRDRowCount2h
As per RRDRowCount, but for the RRA's -typically- used for 2 hour data.
Even so, you must still take the base interval into account. Leaving
out this keyword will force the old default of 800 rows.
Example:
RRDRowCount2h[myrouter]: 400
RRDRowCount1d
As per RRDRowCount, but for the RRA's -typically- used for 1 day data.
Even so, you must still take the base interval into account. Leaving
out this keyword will force the old default of 800 rows.
Example:
RRDRowCount1d[myrouter]: 200
RRDHWRRAs
Normally the RRDs created by MRTG will just contain the information
gathered directly from the respective target. With this option you can
tap into rrdtools advanced aberrant behaviour detection module based on
Holt-Winters forecasting. The RRDHWRRAs property specifies the Holt-
Winters RRAs as described in the rrdcreate manual page.
Note, this setting will only affect newly created RRDs (targets).
Example:
RRDHWRRAs[myrouter]: RRA:HWPREDICT:1440:0.1:0.0035:288
TimeStrPos
This defines placement of the timestamp string on the image. Possible
values are RU, LU, RL, LL (which stand, respectively, for RightUpper,
LeftUpper, RightLower and LeftLower corner) and NO (for no timestamp).
By default, no timestamp is placed on the image.
Example:
TimeStrPos[myrouter]: RU
TimeStrFmt
Using this keyword you may specify format of the timestamp to be placed
on the image (if enabled by the TimeStrPos keyword). Specified string
will be used by the strftime() function - see strftime(3) documentation
for conversion specifiers available on your system. Default format:
%Y-%m-%d %H:%M
Example:
TimeStrFmt[myrouter]: %H:%M:%S
THRESHOLD CHECKING
Through its threshold checking functionality mrtg is able to detect
threshold problems for the various targets and can call external
scripts to handle those problems (e.g. send email or a page to an
administrator).
Threshold checking is configured through the following parameters:
ThreshDir (GLOBAL)
By defining ThreshDir to point to a writable directory, MRTG will only
alert you when a threshold boundary has been crossed.
Example:
ThreshDir: /var/mrtg/thresh
ThreshHyst (GLOBAL)
If a threshold is broken, and you have a threshdir defined, then mrtg
will send mail once the threshold becomes 'unborken' to avoid
situations where broken and unbroken messages get sent in close
succession, we only send an unbroken message once the curent value is
0.1 (10%) away from the threshold. using the ThreshHyst config
variable you can customize this value.
Example for 5%:
ThreshHyst: 0.05
ThreshMailServer (GLOBAL)
Adderss of an SMTP server which is going to accept mail about
Thresholds being broken and unbroken.
ThreshMailSender (GLOBAL)
What is the sender address of the threshold mail.
Example:
ThreshMailSender: mrtg@example.com
ThreshMailAddress (PER TARGET)
Email address for Threshold related Mails. This will only work if a
mailserver has been configured.
Example:
ThreshMailAddress[_]: admin@example.com
ThreshMailAddress[router]:
This would bring threshold releaed mail to all but the target called
'router'.
ThreshMinI (PER TARGET)
This is the minimum acceptable value for the Input (first) parameter.
If the parameter falls below this value, the program specified in
ThreshProgI will be run and a mail will be sent to the
ThreshMailAddress if specified. If the value ends in '%' then the
threshold is defined relative to MaxBytes.
ThreshMaxI (PER TARGET)
Works the same as TheshMinI but it acts when the value is higher than
ThreshMaxI.
ThreshDesc (PER TARGET)
Its value will be assigned to the environment variable THRESH_DESC
before any of the programs mentioned below are called. The programs can
use the value of this variable to produce more user-friendly output.
ThreshProgI (PER TARGET)
This defines a program to be run if ThreshMinI or ThreshMaxI is broken.
MRTG passes 3 arguments: the $router variable, the threshold value
broken, and the current parameter value.
ThreshProgOKI (PER TARGET)
This defines a program to be run if the parameter is currently OK
(based on ThreshMinI and ThreshMaxI), but wasn't OK on the previous
running -- based on the files found in ThreshDir. MRTG passes 3
arguments: the $router variable the unbroken threshold value, and the
current parameter value.
ThreshMinO, ThreshMaxO, ThreshProgO, and ThreshProgOKO
These work the same as their *I counterparts, except on the Output
(second) parameter.
SetEnv
When calling threshold scripts from within your cfg file you might want
to pass some data on to the script. This can be done with the SetEnv
configuration option which takes a series of environment variable
assignments. Note that the quotes are mandatory. This does not work for
external scripts. It is not possible to set environment variables per
target.
Example:
SetEnv[myrouter]: EMAIL="contact_email@someplace.net"
HOST="www.some_server.net"
HW Failure Bassed Threshold Checking
When using rrd based logging with HW RRAs defined. You can use the
confidence bounds violations stored in the FAILURES RRA for threshold
based alerts.
There the all target specific threshold variables have a Hold-Winters
counterpart:
ThreshMailAddress -> HWThreshMailAddress
ThreshMinI -> HWThreshMinI
...
The global variables for threshold checking are shared except for the
ThreshHyst -> HWThreshHyst
And HWThreshDesc sets the HWTHRESH_DESC variable.
PER TARGET DEFAULT VALUES
Pre- and Postfix
To save yourself some typing you can define a target called '^'. The
text of every Keyword you define for this target will be PREPENDED to
the corresponding Keyword of all the targets defined below this line.
The same goes for a Target called '$' but its text will be APPENDED.
Note that a space is inserted between the prepended text and the
Keyword value, as well as between the Keyword value and the appended
text. This works well for text-valued Keywords, but is not very useful
for other Keywords. See the "default" target description below.
The example will make mrtg use a common header and a common contact
person in all the pages generated from targets defined later in this
file.
Example:
PageTop[^]: <H1>NoWhere Unis Traffic Stats</H1><HR>
PageTop[$]: Contact Peter Norton if you have any questions<HR>
To remove the prepend/append value, specify an empty value, e.g.:
PageTop[^]:
PageTop[$]:
NoSpaceChar
With PREPEND and APPEND (see below) there is normally a space inserted
between the local value and the PRE- or APPEND value. Sometimes this is
not desirable. You can use the global option NoSpaceChar to define a
character which can be mentioned at the end of a $ or ^ definition in
order to supress the space.
Example:
NoSpaceChar: ~
Target[^]: 1.3.6.1.4.1.482.50.2.4.20.0&1.3.6.1.4.1.482.50.2.4.21.0:get@~
Target[a]: a.tolna.net
Target[b]: b.tolna.net
Target[c]: c.tolna.net
Target[d]: d.tolna.net
Default Values
The target name '_' specifies a default value for that Keyword. In the
absence of explicit Keyword value, the prepended and the appended
keyword value, the default value will be used.
Example:
YSize[_]: 150
Options[_]: growright,bits,nopercent
WithPeak[_]: ymw
Suppress[_]: y
MaxBytes[_]: 1250000
To remove the default value and return to the 'factory default',
specify an empty value, e.g.:
YLegend[_]:
There can be several instances of setting the default/prepend/append
values in the configuration file. The later setting replaces the
previous one for the rest of the configuration file. The
default/prepend/append values used for a given keyword/target pair are
the ones that were in effect at the point in the configuration file
where the target was mentioned for the first time.
Example:
MaxBytes[_]: 1250000
Target[myrouter.somplace.edu.2]: 2:public@myrouter.somplace.edu
MaxBytes[_]: 8000
Title[myrouter.somplace.edu.2]: Traffic Analysis for myrouter.somplace.edu IF 2
The default MaxBytes for the target myrouter.someplace.edu.2 in the
above example will be 1250000, which was in effect where the target
name myrouter.someplace.edu.2 first appeared in the config file.
COMMAND LINE OPTIONS--user username and --group groupname
Run as the given user and/or group. (Unix Only)
--lock-file filename
Use an alternate lock-file (the default is to use the
configuration-file appended with "_l").
--confcache-file filename
Use an alternate confcache-file (the default is to use the
configuration-file appended with ".ok")
--logging filename|eventlog
If this is set to writable filename, all output from mrtg
(warnings, debug messages, errors) will go to filename. If you are
running on Win32 you can specify eventlog instead of a filename
which will send all error to the windows event log.
NOTE: Note, there is no Message DLL for mrtg included with mrtg.
This has the side effect that the windows event logger will display
a nice message with every entry in the event log, complaing about
the fact that mrtg has no message dll. If you go to the mrtg
contrib download area (on the website) you will find the
mrtg-message-dll.zip which does contain such a thing.
--daemon
Put MRTG into the background, running as a daemon. This works the
same way as the config file option, but the switch is required for
proper FHS operation (because /var/run is writable only by root)
--fhs
Configure all mrtg paths to conform to the FHS specification;
http://www.pathname.com/fhs/
--check
Only check the cfg file for errors. Do not do anything.
--pid-file=s
Define the name and path of the pid file for mrtg running as a
daemon
--debug=s
Enable debug options. The argument of the debug option is a comma
separated list of debug values:
cfg - watch the config file reading
dir - directory mangeling
base - basic program flow
tarp - target parser
snpo - snmp polling
coca - confcache operations
fork - forking view
time - some timing info
log - logging of data via rateup or rrdtool
eval - print eval strings before evaluting them
prof - add hires timing info the rrd calls
Example:
--debug="cfg,snpo"
EXIT CODES
An exit code of 0 indicates that all targets were successful.
Generally speaking, most codes greater than 0 indicate that there was
an unrecoverable problem. One exception to this is code 91, which
indicates that at least one of the targets was successful. A partial
listing of the codes follows:
0: All targets sucessful
2: Config error (can't read, fatal error in config, etc)
17: Another MRTG process is processing config
91: At least one target sucessful
92: No targets were sucessful
EXAMPLES
Minimal mrtg.cfg
WorkDir: /usr/tardis/pub/www/stats/mrtg
Target[r1]: 2:public@myrouter.somplace.edu
MaxBytes[r1]: 8000
Title[r1]: Traffic Analysis ISDN
PageTop[r1]: <H1>Stats for our ISDN Line</H1>
Cfg for several Routers.
WorkDir: /usr/tardis/pub/www/stats/mrtg
Title[^]: Traffic Analysis for
PageTop[^]: <H1>Stats for
PageTop[$]: Contact The Chief if you notice anybody<HR>
MaxBytes[_]: 8000
Options[_]: growright
Title[isdn]: our ISDN Line
PageTop[isdn]: our ISDN Line</H1>
Target[isdn]: 2:public@router.somplace.edu
Title[backb]: our Campus Backbone
PageTop[backb]: our Campus Backbone</H1>
Target[backb]: 1:public@router.somplace.edu
MaxBytes[backb]: 1250000
# the following line removes the default prepend value
# defined above
Title[^]:
Title[isdn2]: Traffic for the Backup ISDN Line
PageTop[isdn2]: our ISDN Line</H1>
Target[isdn2]: 3:public@router.somplace.edu
AUTHOR
Tobias Oetiker <tobi@oetiker.ch> and many contributors
2.17.2 2011-02-20 MRTG-REFERENCE(1)
