The Ultimate Guide to High Availability with MariaDB

Upgrading Between Minor Versions with Galera Cluster

Performing a Rolling Upgrade

The following steps can be used to perform a rolling upgrade between minor versions of MariaDB (for example from MariaDB 10.3.12 to MariaDB 10.3.13) when Galera Cluster is being used. In a rolling upgrade, each node is upgraded individually, so the cluster is always operational. There is no downtime from the application's perspective.

Before you upgrade, it would be best to take a backup of your database. This is always a good idea to do before an upgrade. We would recommend Mariabackup.

For each node, perform the following steps:

  1. Stop MariaDB.
  2. Install the new version of MariaDB and the Galera wsrep provider.
  3. Make any desired changes to configuration options in option files, such as my.cnf. This includes removing any system variables or options that are no longer supported.
  4. Start MariaDB.
  5. Run mariadb-upgrade ( the --skip-write-binlog option is important in this step. While it is not necessary to specify it on the command-line because it is on by default, specifying it can help as a reminder that it is needed)
    • mariadb-upgrade does two things:
      1. Ensures that the system tables in the mysql database are fully compatible with the new version.
      2. Does a very quick check of all tables and marks them as compatible with the new version of MariaDB .

When this process is done for one node, move onto the next node.

Note that when upgrading the Galera wsrep provider, sometimes the Galera protocol version can change. The Galera wsrep provider should not start using the new protocol version until all cluster nodes have been upgraded to the new version, so this is not generally an issue during a rolling upgrade. However, this can cause issues if you restart a non-upgraded node in a cluster where the rest of the nodes have been upgraded.

Comments

 
7 months, 2 weeks ago Manuel Dejonghe
Re: Upgrading Between Minor Versions with Galera Cluster

However, this can cause issues if you restart a non-upgraded node in a cluster where the rest of the nodes have been upgraded.

What is meant by upgrading the rest of the nodes? Doesn't upgrading a node require restarting?

When exactly do nodes (or the whole cluster) switch to the new wsrep protocol version? When all known nodes of a cluster have upgraded the wsrep provider? Or when all nodes that are online have upgraded the wsrep provider? Or sth else?

Thanks!

/fn

 
4 years, 5 months ago Oli Sennhauser
Re: Upgrading Between Minor Versions with Galera Cluster

Can anybody explain why mysql_upgrade/mariadb-upgrade should be called with the option --skip-write-binlog?

The default is write_binlog = false anyway:

mariadb-upgrade --help | grep ^write-binlog write-binlog FALSE

 
2 years, 11 months ago Oliver Kelm
Re: Upgrading Between Minor Versions with Galera Cluster

Have you found any answer regarding your question? On a Debian machines there is startup-script (/etc/mysql/debian-start) which runs mysql_upgrade on each start. I was just wondering, if I should remove this script (and run it manually) or add the --skip-write-brinlog to it.... (it's a galera cluster)

 
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