Configuring the Xpand Monitor
Configuring the Xpand Monitor
NOTE The Xpand monitor is intended for use with a native Xpand cluster, not with the Xpand storage engine.
This document describes how to configure the Xpand monitor for use with a Xpand cluster.
Configuring the Monitor
Contrary to the other monitors of MaxScale, the Xpand monitor will autonomously figure out the cluster configuration and for each Xpand node create the corresponding MaxScale server object.
In order to do that, a sufficient number of "bootstrap" server instances must be specified in the MaxScale configuration file for the Xpand monitor to start with. One server instance is in principle sufficient, but if the corresponding node happens to be down when MaxScale starts, the monitor will not be able to function.
[Bootstrap1] type=server address=10.2.224.101 port=3306 protocol=mariadbbackend [Bootstrap2] type=server address=10.2.224.102 port=3306 protocol=mariadbbackend
The server configuration is identical with that of any other server, but since these servers are only used for bootstrapping the Xpand monitor it is adviceable to use names that clearly will identify them as such.
The actual Xpand monitor configuration looks as follows:
[Xpand] type=monitor module=xpandmon servers=Bootstrap1, Bootstrap2 user=monitor_user password=monitor_password monitor_interval=2000 cluster_monitor_interval=60000
The mandatory parameters are the object type, the monitor module to use, the list of servers to use for bootstrapping and the username and password to use when connecting to the servers.
monitor_interval parameter specifies how frequently the monitor should
ping the health check port of each server and the
specifies how frequently the monitor should do a complete cluster check, that
is, access the
system tables of the Cluster for checking the Cluster
configuration. The default values are
60000, that is, 2 seconds
and 1 minute, respectively.
For each detected Xpand node a corresponding MaxScale server object will be
created, whose name is
@@<Monitor-Name>:node-<id>, where _Monitor-Name_
is the name of the monitor, in this exampleXpand` and id is the node id
of the Xpand node. So, with a cluster of three nodes, the created servers
might be named like.
@@Xpand:node-2` @@Xpand:node-3` @@Xpand:node-7`
Note that as these are created at runtime and may disappear at any moment, depending on changes happening in and made to the Xpand cluster, they should never be referred to directly from service configurations. Instead, services should refer to the monitor, as shown in the following:
[MyService] type=service router=readconnroute user=service_user password=service_password cluster=Xpand
Instead of listing the servers of the service explicitly using the
parameter as usually is the case, the service refers to the Xpand monitor
cluster parameter. This will cause the service to use the Xpand
nodes that the Xpand monitor discovers at runtime.
For additional details, please consult the monitor documentation.