IBM Streams 4.2.1

Removing resources

You might choose to remove a resource if the host is no longer available or you want to replace it with a different resource. When you remove a resource from a domain or instance, there must be other resources available for the jobs to remain healthy.

Before you begin

To remove a resource from an instance, you must have delete and search authority for the hosts instance object.

To remove a resource from a domain, you must have delete and search authority for the config domain object.

For more information, see User authorization for IBM® Streams.

About this task

Before IBM Streams removes resources from an instance, it verifies that the instance and the relevant jobs can remain healthy without these resources. If there are any management services on these resources, standby services must be configured and available for the instance to remain healthy. For the jobs to remain healthy, there must be another resource in the instance that meets the placement constraints of all processing elements that are currently running on the resource. For more information, see Configuring high availability in an IBM Streams enterprise domain.

Procedure

To remove a resource from an instance or to change its resource specifications, use the Streams Console. Alternatively, you can use one of the following streamtool commands: streamtool rmhost, streamtool chresourcespec, or streamtool rmresourcespec.
To remove a resource from a domain:
1. Stop or quiesce the resource. You cannot remove a resource from a domain when there are IBM Streams services other than the domain controller service that are running on the resource. You must quiesce or stop the resource before you remove it.
2. Remove the resource from the domain.
  - To remove an IBM Streams resource, use the Streams Console or the streamtool rmdomainhost or streamtool unregisterdomainhost commands.
    Note:
    - If the resource is the last remaining resource in the domain, you cannot remove it. You must use the streamtool rmdomain command to remove the domain.
    - If the resource is an IBM Streams resource and the domain controller service is stopped, you must use the streamtool unregisterdomainhost command. If the domain controller service is a system service and you want to remove it, you must also use that command.
  - To remove an externally managed resource, use your external resource manager.

Results

When you remove a resource from an instance, IBM Streams performs a controlled shutdown of the processing elements on the resource. The processing elements are relocated. The resource is also removed from the instance configuration. If one or more processing elements cannot be relocated, the removal fails.

When you remove a resource from a domain, IBM Streams contacts the domain controller service that is running on the resource. This service performs the removal and then stops.