MOSQUITTO(8) System management commands MOSQUITTO(8)NAMEmosquitto - an MQTT broker
SYNOPSISmosquitto [-c config file] [-d | --daemon] [-p port number] [-v]
DESCRIPTIONmosquitto is a broker for the MQTT protocol version 3.1.
OPTIONS-c, --config-file
Load configuration from a file. If not given, the default values as
described in mosquitto.conf(5) are used.
-d, --daemon
Run mosquitto in the background as a daemon. All other behaviour
remains the same.
-p, --port
Listen on the port specified instead of the default 1883. This acts
in addition to the port setting in the config file. May be
specified multiple times to open multiple sockets listening on
different ports. This socket will be bound to all network
interfaces.
-v, --verbose
Use verbose logging. This is equivalent to setting log_type to all
in the configuration file. This overrides and logging options given
in the configuration file.
CONFIGURATION
The broker can be configured using a configuration file as described in
mosquitto.conf(5) and this is the main point of information for
mosquitto. The files required for SSL/TLS support are described in
mosquitto-tls(7).
BROKER STATUS
Clients can find information about the broker by subscribing to topics
in the $SYS hierarchy as follows. Topics marked as static are only sent
once per client on subscription. All other topics are updated every
sys_interval seconds. If sys_interval is 0, then updates are not sent.
$SYS/broker/bytes/received
The total number of bytes received since the broker started.
$SYS/broker/bytes/sent
The total number of bytes sent since the broker started.
$SYS/broker/changeset
The repository changeset (revision) associated with this build.
Static.
$SYS/broker/clients/active
The number of currently connected clients
$SYS/broker/clients/expired
The number of disconnected persistent clients that have been
expired and removed through the persistent_client_expiration
option.
$SYS/broker/clients/inactive
The total number of persistent clients (with clean session
disabled) that are registered at the broker but are currently
disconnected.
$SYS/broker/clients/maximum
The maximum number of active clients that have been connected to
the broker. This is only calculated when the $SYS topic tree is
updated, so short lived client connections may not be counted.
$SYS/broker/clients/total
The total number of active and inactive clients currently connected
and registered on the broker.
$SYS/broker/connection/#
When bridges are configured to/from the broker, common practice is
to provide a status topic that indicates the state of the
connection. This is provided within $SYS/broker/connection/ by
default. If the value of the topic is 1 the connection is active,
if 0 then it is not active. See the Bridges section below for more
information on bridges.
$SYS/broker/heap/current size
The current size of the heap memory in use by mosquitto. Note that
this topic may be unavailable depending on compile time options.
$SYS/broker/heap/maximum size
The largest amount of heap memory used by mosquitto. Note that this
topic may be unavailable depending on compile time options.
$SYS/broker/load/connections/+
The moving average of the number of CONNECT packets received by the
broker over different time intervals. The final "+" of the
hierarchy can be 1min, 5min or 15min. The value returned represents
the number of connections received in 1 minute, averaged over 1, 5
or 15 minutes.
$SYS/broker/load/bytes/received/+
The moving average of the number of bytes received by the broker
over different time intervals. The final "+" of the hierarchy can
be 1min, 5min or 15min. The value returned represents the number of
bytes received in 1 minute, averaged over 1, 5 or 15 minutes.
$SYS/broker/load/bytes/sent/+
The moving average of the number of bytes sent by the broker over
different time intervals. The final "+" of the hierarchy can be
1min, 5min or 15min. The value returned represents the number of
bytes sent in 1 minute, averaged over 1, 5 or 15 minutes.
$SYS/broker/load/messages/received/+
The moving average of the number of all types of MQTT messages
received by the broker over different time intervals. The final "+"
of the hierarchy can be 1min, 5min or 15min. The value returned
represents the number of messages received in 1 minute, averaged
over 1, 5 or 15 minutes.
$SYS/broker/load/messages/sent/+
The moving average of the number of all types of MQTT messages sent
by the broker over different time intervals. The final "+" of the
hierarchy can be 1min, 5min or 15min. The value returned represents
the number of messages send in 1 minute, averaged over 1, 5 or 15
minutes.
$SYS/broker/load/publish/dropped/+
The moving average of the number of publish messages dropped by the
broker over different time intervals. This shows the rate at which
durable clients that are disconnected are losing messages. The
final "+" of the hierarchy can be 1min, 5min or 15min. The value
returned represents the number of messages dropped in 1 minute,
averaged over 1, 5 or 15 minutes.
$SYS/broker/load/publish/received/+
The moving average of the number of publish messages received by
the broker over different time intervals. The final "+" of the
hierarchy can be 1min, 5min or 15min. The value returned represents
the number of publish messages received in 1 minute, averaged over
1, 5 or 15 minutes.
$SYS/broker/load/publish/sent/+
The moving average of the number of publish messages sent by the
broker over different time intervals. The final "+" of the
hierarchy can be 1min, 5min or 15min. The value returned represents
the number of publish messages sent in 1 minute, averaged over 1, 5
or 15 minutes.
$SYS/broker/load/sockets/+
The moving average of the number of socket connections opened to
the broker over different time intervals. The final "+" of the
hierarchy can be 1min, 5min or 15min. The value returned represents
the number of socket connections in 1 minute, averaged over 1, 5 or
15 minutes.
$SYS/broker/messages/inflight
The number of messages with QoS>0 that are awaiting
acknowledgments.
$SYS/broker/messages/received
The total number of messages of any type received since the broker
started.
$SYS/broker/messages/sent
The total number of messages of any type sent since the broker
started.
$SYS/broker/messages/stored
The number of messages currently held in the message store. This
includes retained messages and messages queued for durable clients.
$SYS/broker/publish/messages/dropped
The total number of publish messages that have been dropped due to
inflight/queuing limits. See the max_inflight_messages and
max_queued_messages options in mosquitto.conf(5) for more
information.
$SYS/broker/publish/messages/received
The total number of PUBLISH messages received since the broker
started.
$SYS/broker/publish/messages/sent
The total number of PUBLISH messages sent since the broker started.
$SYS/broker/retained messages/count
The total number of retained messages active on the broker.
$SYS/broker/subscriptions/count
The total number of subscriptions active on the broker.
$SYS/broker/timestamp
The timestamp at which this particular build of the broker was
made. Static.
$SYS/broker/uptime
The amount of time in seconds the broker has been online.
$SYS/broker/version
The version of the broker. Static.
WILDCARD TOPIC SUBSCRIPTIONS
In addition to allowing clients to subscribe to specific topics,
mosquitto also allows the use of two wildcards in subscriptions. + is
the wildcard used to match a single level of hierarchy. For example,
for a topic of "a/b/c/d", the following example subscriptions will
match:
· a/b/c/d
· +/b/c/d
· a/+/c/d
· a/+/+/d
· +/+/+/+
The following subscriptions will not match:
· a/b/c
· b/+/c/d
· +/+/+
The second wildcard is # and is used to match all subsequent levels of
hierarchy. With a topic of "a/b/c/d", the following example
subscriptions will match:
· a/b/c/d
· #
· a/#
· a/b/#
· a/b/c/#
· +/b/c/#
The $SYS hierarchy does not match a subscription of "#". If you want to
observe the entire $SYS hierarchy, subscribe to $SYS/#.
Note that the wildcards must be only ever used on their own, so a
subscription of "a/b+/c" is not valid use of a wildcard. The # wildcard
must only ever be used as the final character of a subscription.
BRIDGES
Multiple brokers can be connected together with the bridging
functionality. This is useful where it is desirable to share
information between locations, but where not all of the information
needs to be shared. An example could be where a number of users are
running a broker to help record power usage and for a number of other
reasons. The power usage could be shared through bridging all of the
user brokers to a common broker, allowing the power usage of all users
to be collected and compared. The other information would remain local
to each broker.
For information on configuring bridges, see mosquitto.conf(5).
SIGNALS
SIGHUP
Upon receiving the SIGHUP signal, mosquitto will attempt to reload
configuration file data, assuming that the -c argument was provided
when mosquitto was started. Not all configuration parameters can be
reloaded without restarting. See mosquitto.conf(5) for details.
SIGUSR1
Upon receiving the SIGUSR1 signal, mosquitto will write the
persistence database to disk. This signal is only acted upon if
persistence is enabled.
SIGUSR2
The SIGUSR2 signal causes mosquitto to print out the current
subscription tree, along with information about where retained
messages exist. This is intended as a testing feature only and may
be removed at any time.
FILES
/etc/mosquitto/mosquitto.conf
Configuration file. See mosquitto.conf(5).
/var/lib/mosquitto/mosquitto.db
Persistent message data storage location if persist enabled.
/etc/hosts.allow, /etc/hosts.deny
Host access control via tcp-wrappers as described in
hosts_access(5).
BUGSmosquitto bug information can be found at
http://launchpad.net/mosquitto
SEE ALSOmqtt(7), mosquitto-tls(7), mosquitto.conf(5), hosts_access(5),
mosquitto_passwd(1), mosquitto_pub(1), mosquitto_sub(1),
libmosquitto(3)THANKS
Thanks to Andy Stanford-Clark for being one of the people who came up
with MQTT in the first place. Thanks to Andy and Nicholas O'Leary for
providing clarifications of the protocol.
Thanks also to everybody at the Ubuntu UK Podcast and Linux Outlaws for
organising OggCamp, where Andy gave a talk that inspired mosquitto.
ACKNOWLEDGEMENTS
This product includes software developed by the OpenSSL Project for use
in the OpenSSL Toolkit. (http://www.openssl.org/)
This product includes cryptographic software written by Eric Young
(eay@cryptsoft.com)
This product includes software written by Tim Hudson
(tjh@cryptsoft.com)
AUTHOR
Roger Light <roger@atchoo.org>
Mosquitto Project 03/24/2014 MOSQUITTO(8)
