InitShardMaster

The InitShardMaster step initializes the quorum by electing a primary and setting up replication for the replicas. Additionally, a database is created to store the data for the keyspace-shard. The default name for the database will be vt_ followed by the keyspace. In our use case, it would be vt_commerce. You can override this default by providing an init_db_name_override flag to vttablet. However, all future invocations must continue to supply this parameter.

The command for InitShardMaster is as follows:

vtctlclient \
  InitShardMaster \
  -force \
  commerce/0 \
  cell1-100

Until this command is run, you may also see errors like this in the vttablet logs: Cannot start query service: Unknown database 'vt_xxx'. This is because the database will be created only after a primary is elected.

If you have semi-sync enabled and did not set up at least three replicas, InitiShardMaster could hang indefinitely. Even if it succeeds, future operations that perform failovers could cause this shard to go into a deadlocked state.

After this step, visiting the /debug/status page on the vttablets should show all the tablets as healthy:

healthy-tablet

InitShardMaster is a destructive command that resets all servers by deleting their binlog metadata. It should only be used for initializing a brand new cluster.
InitShardMaster will soon be deprecated. This action will be performed automatically by vtorc once it is released as production-ready.

InitShardMaster