You can use the MySQL Performance Schema to monitor Group Replication. These Performance Schema tables display information specific to Group Replication:
These Performance Schema replication tables also show information relating to Group Replication:
replication_connection_statusshows information regarding Group Replication, such as transactions received from the group and queued in the applier queue (relay log).
replication_applier_statusshows the states of channels and threads relating to Group Replication. These can also be used to monitor what individual worker threads are doing.
Replication channels created by the Group Replication plugin are listed here:
group_replication_recovery: Used for replication changes related to distributed recovery.
group_replication_applier: Used for the incoming changes from the group, to apply transactions coming directly from the group.
If you are monitoring one or more secondary instances using
mysqladmin, you should be aware that a
FLUSH STATUS statement executed by
this utility creates a GTID event on the local instance which may
impact future group operations.