Migrating to multiple Kudu masters

To provide high availability and to avoid a single point of failure, Kudu clusters should be created with multiple masters. Many Kudu clusters were created with just a single master, either for simplicity or because Kudu multi-master support was still experimental at the time. This workflow demonstrates how to migrate to a multi-master configuration. It can also be used to migrate from two masters to three with straightforward modifications.

important

This workflow is unsafe for adding new masters to an existing multi-master configuration that already has three or more masters. Do not use it for that purpose.
An even number of masters doesn't provide any benefit over having one fewer masters. This guide should always be used for migrating to three masters.
This workflow presumes you are familiar with Kudu configuration management, with or without Cloudera Manager.
All of the command line steps below should be executed as the Kudu UNIX user. The example commands assume the Kudu Unix user is kudu, which is typical.