Decommission or remove a tablet server

You can decommission or permanently remove a tablet server from a cluster.

Starting with Kudu 1.12, the Kudu rebalancer tool can be used to decommission a tablet server by supplying the --ignored_tservers and --move_replicas_from_ignored_tservers arguments.

Ensure the cluster is in good health using ksck.
Put the tablet server into a maintenance mode by using the kudu tserver state enter_maintenance tool.
Run the kudu cluster rebalance tool, supplying the --ignored_tservers argument with the UUIDs of the tablet servers to be decommissioned, and the --move_replicas_from_ignored_tservers flag.
Wait for the moves to complete and for ksck to show the cluster in a healthy state.

note
To verify that all the moves are completed from the server placed in maintenance mode, ensure that there are no replicas on the server by running kudu cluster ksck or running kudu cluster rebalancer with --report_only and --output_replica_distribution_details flags or checking the Web UI of the tablet server.
The decommissioned tablet server can be brought offline by stopping the tablet server in Cloudera Manager.
To completely remove it from the cluster so ksck shows the cluster as completely healthy, restart the masters.
If you have only one master in your deployment, this may cause cluster downtime. In a multi-master deployment, restart the masters in sequence to avoid cluster downtime.