rolling upgrade

Because upgrading from MariaDB 10.4 to MariaDB 10.5 (non-clustered) seems not to be a problem [ 1 ] we take the challenge and try to create a receipt based on the MariaDB 10.3 to MariaDB 10.4 Galera Cluster upgrade documentation [ 3 ]:

Before you start

Before you begin with the upgrade you should consider a few things:

A few days ago Codership announced their new version Galera v1.1 - synchronous Replication Cluster for MySQL. Before we look at the new feature of Rolling Online Schema Upgrade (OSU) we have a look at how to upgrade to the new Galera release.