Maintenance in Managed Service for OpenSearch

Maintenance includes:

• Automatic installation of OpenSearch updates and patches for host groups (including for stopped clusters).
• Scheduled automatic storage expansion.
• Other maintenance activities.

A major DBMS version update is not part of maintenance. For more information about upgrading between major versions, see OpenSearch version upgrade.

Maintenance windowMaintenance window

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

• The At any time option (default) allows performing maintenance at any time.
• The By schedule option allows you to select the day of the week and UTC time when the maintenance will be performed. For example, you can choose a time when the cluster is least loaded.

Maintenance workflowMaintenance workflow

In Managed Service for OpenSearch single-host clusters, a single host undergoes maintenance. This means, if you restart such a cluster during maintenance, it will become unavailable.

In multi-host clusters, hosts undergo maintenance one by one. Such hosts are queued randomly. Any host that requires a restart during maintenance will be unavailable until maintenance is complete. If you access a cluster using the FQDN of the OpenSearch host, the cluster may become unavailable. To make your application continuously available, access the cluster using a special FQDN always pointing to the available host.