The mandatory parameters are the object type, the monitor module to use, the list of servers to monitor and the username and password to use when connecting to the servers. The monitor_interval parameter controls for how long the monitor waits between each monitoring loop.
This monitor module will assign one node within the Galera Cluster as the current primary and other nodes as replica. Only those nodes that are active members of the cluster are considered when making the choice of primary node. The primary node will be the node with the lowest value of wsrep_local_index.
Monitor User
The monitor user does not require any special grants to monitor a Galera cluster. To create a user for the monitor, execute the following SQL.
CREATE USER 'monitor_user'@'%' IDENTIFIED BY 'my_password';