I have been using mysql master:master replication and was always able to check the status of replication using this command:
mysql > show slave status\G
I was able to see this in the show slave status command:
The seconds_behind_master always let me know if I was behind on one of my servers.
I am not using galera and am not sure how to verify if everything is up to date.
I have come across this article "Monitoring Cluster Status"
I realize I can use this command to see how many nodes are in the cluster:
SHOW GLOBAL STATUS LIKE 'wsrep_cluster_size';
But I am not sure if this command if good enough to tell whether or not they are exactly up to date:
SHOW GLOBAL STATUS LIKE 'wsrep_local_state_comment';
This command currently show synced but I cannot tell if this is the best way to tell if I am good to go.