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 major version changes, see OpenSearch version upgrade.

Maintenance windowMaintenance window

You can set the maintenance window 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 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. If you restart a host during maintenance, it will become unavailable for this time period. 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.