Advanced MySQL 8

Checking instance states

If you want to verify that an instance is good enough to join a cluster, you can use the cluster.checkInstanceState() function. This function validates a GTID and compares it to GTIDs already processed by a cluster. It also checks whether an instance that has processed transactions can be added to a cluster:

mysql-js> cluster.checkInstanceState('cluster_admin@node4:3306')

The output of the preceding function can be any of the following:

• OK new: Where the instance has not executed any GTID transactions, and cannot conflict with the GTIDs executed by the cluster
• OK recoverable: Where the instance has executed GTIDs that do not conflict with the executed GTIDs of the cluster seed instances
• ERROR diverged: Where the ...