Scale an Oracle SOA Cloud Service cluster to add nodes to or remove nodes from the cluster in response to changes in the load on the cluster. A node is a virtual machine (VM) running a managed server instance that is a member of a cluster.
About Scaling Out an Oracle SOA Cloud Service Cluster
Scaling out an Oracle SOA Cloud Service cluster adds one node to the cluster.
Before scaling out an Oracle SOA Cloud Service cluster, ensure that all these conditions are met:
You have the Oracle SOA administrator role as described in About Oracle SOA Cloud Service Roles and User Accounts.
The service instance is not under maintenance.
If any of these conditions is not met, the scaling operation fails and Oracle SOA Cloud Service logs an error message.
Oracle SOA Cloud Service logs a message when scaling out is started or completed, or when a failure is detected. You can view these messages as explained in Viewing Scaling Requests.
If an attempt to scale out a cluster fails, Oracle SOA Cloud 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 VM that it created to run the additional managed server instance.
About Scaling In an Oracle SOA Cloud Service Cluster
Scaling in an Oracle SOA Cloud Service cluster removes the selected node from the cluster.
Before scaling in an Oracle SOA Cloud Service cluster, ensure that the cluster contains at least one managed server node in addition to the node for the administration server and first managed server. You cannot scale in a cluster that contains only the node for the administration server and first managed server. If you no longer require that node, you must delete the entire service instance. For instructions, see Deleting an Oracle SOA Cloud Service Instance.
By default, Oracle SOA Cloud Service scales in a cluster gracefully by shutting down the managed server instance before removing the managed server instance from the cluster and terminating its VM. To ensure that the node is removed even if the managed server instance is unresponsive, you can choose to forcibly scale in a cluster.
If an attempt to scale in a cluster fails, Oracle SOA Cloud 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.