Maintenance in Managed Service for MySQL®

In Managed Service for MySQL®, maintenance means:

• Automatic installation of DBMS updates and fixes for hosts (including for disabled clusters).
• Other maintenance activities.

Changing a DBMS version is not part of maintenance. For more information about version changes, see MySQL® version upgrade.

Maintenance windowMaintenance window

You can set the preferred maintenance time when creating a cluster or updating its settings:

• The arbitrary option (default) allows performing maintenance at any time.
• The by schedule option allows setting the preferred maintenance start day and time (UTC). For example, you can choose a time when the cluster is least loaded.

Maintenance procedureMaintenance procedure

In Managed Service for MySQL® single-host clusters, a master host undergoes maintenance. Therefore, it may become unavailable in case it is restarted.

In multi-host clusters, the maintenance is run as follows:

1. Replicas undergo maintenance one by one. The replicas are queued randomly. A replica becomes temporarily unavailable if it needs to be restarted during maintenance.
2. Master host undergoes maintenance and gets updated. If it is restarted and becomes unavailable, one of the replicas takes its role. If you access a cluster using the FQDN of the master host, the cluster may become unavailable. To make your application continuously available, access the cluster using a special FQDN that always points to the master host.