About Scaling an Oracle Java Cloud Service Cluster

Add nodes to or remove nodes from a cluster in your Oracle Java Cloud Service instance, in response to changes in the load on the cluster.

Note the following considerations:
  • Scaling a cluster is not supported by Oracle Java Cloud Service—Virtual Image instances.

  • Scaling out the Coherence data tier cluster requires a different procedure. See Scale Out a Coherence Data Grid.

  • If the cluster contains any Managed Servers that were created outside of Oracle Java Cloud Service (for example, by using the WebLogic console), before scaling out the cluster, delete those servers manually or select Force Remove during the Remove Node process.

  • During a scale-out operation, any custom software installations or file system changes on existing nodes are not automatically propagated to the new node.

  • If the service instance was provisioned in a region and assigned reserved IP addresses, you must assign a reserved IP address for the new node.

About Scaling Out a Cluster

Scaling out a cluster adds one node to the cluster.

Before scaling out a cluster, ensure that all these conditions are met:
  • You have the Service Administrator role.

  • The service instance is not under maintenance.

If any of these conditions is not met, the scaling operation fails and the service logs an error message.

The service logs a message when scaling out is started or completed, or when a failure is detected. .

If an attempt to scale out a cluster fails, the service does the following:
  • Logs any diagnostic information.

  • Sets the status of the service instance to RUNNING to allow other operations to continue.

  • Returns the service instance to its original shape.

  • Deletes the node that it created.

About Scaling In a Cluster

Scaling in a cluster removes the selected node from the cluster. You cannot scale in a cluster that contains a single node. If you no longer require that node, you must delete the entire service instance.

By default, the service scales in a cluster gracefully by shutting down any Oracle software running on the node. To ensure that the node is removed even if it is unresponsive, you can choose to forcibly scale in a cluster.

If an attempt to scale in a cluster fails, the service does the following:
  • Logs any diagnostic information.

  • Sets the status of the service instance to RUNNING to allow other operations to continue.

  • Cleans up any stale resources.

About Adding a New Cluster

In some cases, you might want to scale out an instance but a cluster doesn't exist.

You can add a cluster to an instance by using the REST API and include the createClusterIfMissing=true query parameter on the scale out REST endpoint. This operation will not only add the cluster but will scale it out to include a single node.