If a node pool is in a Project, it may be assigned to one or more environments, and pipelines in pipeline sources that share at least one environment with the node pool may use the node pool. By default, node pools are in the DEV environment.
Node pools that are not in a Project are available to pipelines in pipeline sources that are not in a Project. In addition, further restrictions may be specified to restrict use of particular pipeline sources and users that have been given permissionsto use those pipeline sources.
You can establish those usage restrictions when you add or modify a node pool.
Under Assign Pipeines to this Node Pool, uncheck the option for Any Pipeline Source.
In the revealed interface, select from the list of available pipeline sources and move the row(s) (by click-and-drag or arrow button) to the list of included pipeline sources.
When finished, click Save Node Pool.