Lock a Host Using HorizonΒΆ

Locking an unlocked host takes it out of service for configuration and maintenance purposes.

On a controller node, the state transition only succeeds if there are no services running in active mode on the host.

On a worker node (or AIO Controller), the state transition only succeeds if all currently running containers (hosted applications) on the host can be re-located on alternative worker nodes or AIO Controller. Re-location of containers is initiated automatically by StarlingX as soon as the state transition is requested. For containers, a live re-location of the container to another host is attempted. A NoExecute taint, as shown below, is applied to the host, causing any containers on that host to be evicted.



On a StarlingX Simplex system, where re-location of containers is not possible, all running containers are stopped when a host is locked. Other services continue to run.


  1. From Admin > Platform > Host Inventory, select the Hosts tab.

  2. From the Edit menu for the host, select Lock Host.