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$SYS Topics

Feng Lee edited this page Dec 6, 2015 · 13 revisions

NOTICE: This is the design of 0.9.0 release


For emqttd is clustered, $SYS Topics of broker is started with:


${node} is erlang node of clustered brokers. For example:


Broker $SYS Topics

Topic Description
$SYS/brokers Broker nodes
$SYS/brokers/${node}/version Broker Version
$SYS/brokers/${node}/uptime Broker Uptime
$SYS/brokers/${node}/datetime Broker DateTime
$SYS/brokers/${node}/sysdescr Broker Description

Client $SYS Topics

Start with: $SYS/brokers/${node}/clients/

Topic Payload(json) Description
${clientid}/connected {ipaddress: "", username: "test", session: false, version: 3, connack: 0, ts: 1432648482} Publish when client connected
${clientid}/disconnected {reason: "normal" "keepalive_timeout"

Parameters of 'connected' Payload:

ipaddress: "", 
username: "test", 
session: false, 
protocol: 3, 
connack: 0, 
ts: 1432648482

Parameters of 'disconnected' Payload:

reason: normal,
ts: 1432648486

Statistics $SYS Topics

Start with '$SYS/brokers/${node}/stats/'

Client Stats

Topic Description
clients/count count of current connected clients
clients/max max connected clients in the same time

Session Stats

Topic Description
sessions/count count of current sessions
sessions/max max number of sessions

Subscriber Stats

Topic Description
subscriptions/count count of current subscriptions
subscriptions/max max number of subscriptions

Topic Stats

Topic Description
topics/count count of current topics
topics/max max number of topics

Queue Stats

Topic Description
queues/count count of current queues
queues/max max number of queues

Metrics $SYS Topics

Start with '$SYS/brokers/${node}/metrics/'

Bytes sent and received

Topic Description
bytes/received MQTT Bytes Received since broker started
bytes/sent MQTT Bytes Sent since the broker started

Packets sent and received

Topic Description
packets/received MQTT Packets received
packets/sent MQTT Packets sent
packets/connect MQTT CONNECT Packet received
packets/connack MQTT CONNACK Packet sent
packets/publish/received MQTT PUBLISH packets received
packets/publish/sent MQTT PUBLISH packets sent
packets/subscribe MQTT SUBSCRIBE Packets received
packets/suback MQTT SUBACK packets sent
packets/unsubscribe MQTT UNSUBSCRIBE Packets received
packets/unsuback MQTT UNSUBACK Packets sent
packets/pingreq MQTT PINGREQ packets received
packets/pingresp MQTT PINGRESP Packets sent
packets/disconnect MQTT DISCONNECT Packets received

Messages sent and received

Topic Description
messages/received Messages Received
messages/sent Messages Sent
messages/retained Messages Retained
messages/stored TODO: Messages Stored
messages/dropped Messages Dropped

Alarm Topics

Start with '$SYS/brokers/${node}/alarms/'

Topic Description
${alarmId}/alert New Alarm
${alarmId}/clear Clear Alarm



Severity Description
debug Debug Log
info Info Log
notice Notice Log
warning Warning Log
error Error Log
critical Critical Log


Start with '$SYS/brokers/${node}/sysmon/'

Topic Description
long_gc Long GC Warning
long_schedule Long Schedule
large_heap Large Heap Warning
busy_port Busy Port Warning
busy_dist_port Busy Dist Port



Severity Description
debug Debug
info Info Log
notice Notice Log
warning Warning Log
error Error Log
critical Critical Log
alert Alert Log

VM Load Topics

Start with '$SYS/brokers/${node}/vm/'

Topic Description
memory/* TODO
cpu/* TODO
processes/* TODO

Sys Interval

sys_interval: 1 minute default

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