Lock a Host Using Horizon¶
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
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.
From Admin > Platform > Host Inventory, select the Hosts tab.
From the Edit menu for the host, select Lock Host.