MaxScale 1.4 Common Monitor Parameters
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:
$INITIATORwill be replaced with the IP and port of the server who initiated the event$EVENTwill be replaced with the name of the event$NODELISTwill be replaced with a list of server IPs and ports that are running
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 |
