How long a resource must have existed before the periodic orphan cleanup will act on it. This grace period guards against reaping resources that are still being set up. It applies to both directions of cleanup (only relevant when Cleanup Orphaned Agents is enabled):

• Orphaned VMs — a jenkins-managed VM that has no corresponding Jenkins node is only destroyed once it has been running longer than this period. Provisioning clones (and tags) a VM well before its agent is registered, so without the grace a cleanup pass could destroy a VM that is still mid-provisioning. A VM that is not running is treated as already dead and destroyed regardless of this value.
• Dead agent nodes — a persisted agent whose backing VM is gone, or present but not running, is only removed (and any stopped VM destroyed) once the agent has existed longer than this period. This avoids tearing down an agent whose VM is briefly stopped while it boots.

Lower it to reclaim leaked VMs and dead nodes sooner; raise it if your provisioning (clone, boot, cloud-init) regularly takes longer than the default. Cleanup runs roughly every 10 minutes, so a resource is reaped on the first cleanup pass after its grace period elapses. Default: 300 seconds (5 minutes). Minimum: 1.