Perform the removal
When you remove any Kudu masters from a multi-master deployment, you need to rewrite
the Raft configuration on the remaining masters, remove data and WAL directories from the
unwanted masters, and finaly modify the value of the
configuration parameter for the tablet servers to remove the unwanted masters. You need to bring
the Kudu clusters down. Therefore, identify at least a one-hour maintenance window for this
Perform the Raft configuration change by running the
kudu master removetool.Only a single master can be removed at a time. If multiple masters need to be removed, run the tool multiple times. In the following example
master-2is being removed from a Kudu cluster with two masters
$ sudo -u kudu kudu master remove master-1,master-2 master-2
- Remove the data directories and WAL directory on the unwanted masters. This is a precaution to ensure that they cannot start up again and interfere with the new multi-master deployment.
Modify the value of the
master_addressesconfiguration parameter for the masters of the new multi-master deployment.
- Restart all of the masters that were not removed.
If you are not using Cloudera Manager: Modify the value of the
tserver_master_addrsconfiguration parameter for the tablet servers to remove any unwanted masters.
- Retart all of the tablet servers.
Using a browser, visit each master’s web UI and navigate to the
/masterspage. All the masters should now be listed there with one master in the
LEADERrole and the others in the
FOLLOWERrole. The contents of
/masterson each master should be the same.
Run a Kudu system check (
ksck) on the cluster using the
kuducommand line tool.