Common Monitor Parameters

This document lists optional parameters that all current monitors support.

Parameters

monitor_interval

This is the time the monitor waits between each cycle of monitoring. The default value of 10000 milliseconds (10 seconds) should be lowered if you want a faster response to changes in the server states. The value is defined in milliseconds and the smallest possible value is 100 milliseconds.

monitor_interval=2500

backend_connect_timeout

This parameter controls the timeout for connecting to a monitored server. It is in seconds and the minimum value is 1 second. The default value for this parameter is 3 seconds.

backend_connect_timeout=6

backend_write_timeout

This parameter controls the timeout for writing to a monitored server. It is in seconds and the minimum value is 1 second. The default value for this parameter is 2 seconds.

backend_write_timeout=4

backend_read_timeout

This parameter controls the timeout for reading from a monitored server. It is in seconds and the minimum value is 1 second. The default value for this parameter is 1 seconds.

backend_read_timeout=2

script

This command will be executed when a server changes its state. The parameter should be an absolute path to a command or the command should be in the executable path. The user which is used to run MaxScale should have execution rights to the file itself and the directory it resides in.

script=/home/user/myscript.sh initiator=$INITIATOR event=$EVENT live_nodes=$NODELIST

The following substitutions will be made to the parameter value:

  • $INITIATOR will be replaced with the IP and port of the server who initiated the event
  • $EVENT will be replaced with the name of the event
  • $LIST will be replaced with a list of server IPs and ports
  • $NODELIST will be replaced with a list of server IPs and ports that are running
  • $SLAVELIST will be replaced with a list of server IPs and ports that are slaves
  • $MASTERLIST will be replaced with a list of server IPs and ports that are masters
  • $SYNCEDLIST will be replaced with a list of server IPs and ports that are synced Galera nodes

For example, the previous example will be executed as:

/home/user/myscript.sh initiator=[192.168.0.10]:3306 event=master_down live_nodes=[192.168.0.201]:3306,[192.168.0.121]:3306

events

A list of event names which cause the script to be executed. If this option is not defined, all events cause the script to be executed. The list must contain a comma separated list of event names.

events=master_down,slave_down

Script events

Here is a table of all possible event types and their descriptions that the monitors can be called with.

Event Name Description
master_down A Master server has gone down
master_up A Master server has come up
slave_down A Slave server has gone down
slave_up A Slave server has come up
server_down A server with no assigned role has gone down
server_up A server with no assigned role has come up
ndb_down A MySQL Cluster node has gone down
ndb_up A MySQL Cluster node has come up
lost_master A server lost Master status
lost_slave A server lost Slave status
lost_ndb A MySQL Cluster node lost node membership
new_master A new Master was detected
new_slave A new Slave was detected
new_ndb A new MySQL Cluster node was found

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