IBM Streams 4.2.1

Using tags to restrict resources

You can use tags to restrict resources for a specific application purpose by creating a tag restriction between a resource and a tag. This TagRestriction instructs the scheduler to place on the resource only the PEs that refer to a hostpool that specifies that tag.

About this task

In an IBM® Streams domain, you have some resources that you want to restrict for a special purpose where only certain PEs can be scheduled to run. The special purpose resources can be shared across multiple jobs. A TagRestriction provides the capability to restrict the use of a resource at the PE level for multiple jobs.

To achieve this scenario, the following steps are required:
  1. The creation of a TagRestriction between the tag and the resource.
  2. In the SPL application, the existence of an operator with a placement clause that refers to a host pool that contains the tag.
TagRestrictions are subject to the following parameters:
  • A TagRestriction is a relationship between a tag and a resource. It is not a new type of tag or attribute.
  • Only custom tags can be used to restrict resources.
  • Multiple tags can be used to restrict a resource. In this case, the PEs that are allowed to run on the resource are the PEs that refer to a host pool that contains the multiple tags.
  • A TagRestriction can be created and removed with active instances. However when creating the TagRestriction, any PEs running on the resource must reference the host pool containing the tag.
  • A TagRestriction is supported on IBM Streams resources and externally managed resources.
  • Using tags to restrict IBM Streams resources
    You can use tags to restrict IBM Streams resources for a specific application purpose. The TagRestriction that you create instructs the scheduler to place on the resource only the PEs that refer to a host pool that specifies that tag.
  • Using tags to restrict externally managed resources
    You can use tags to restrict externally managed resources for a specific application purpose by creating a tag restriction between the resource and a tag. This TagRestriction instructs the scheduler to place on the resource only the PEs that refer to a hostpool that specifies that tag.
Parent topic: Tags
Related reference:
Streamtool commands