Configure a host to enter or exit maintenance mode
After a host enters maintenance mode, you can shut down, restart, and wake up the host. After you perform these operations, the host is still in maintenance mode. To enable the host to run correctly, configure the host to exit maintenance mode.
Prerequisites
Make sure no running or suspended cloud hosts exist on the host.
Configure a host to enter maintenance mode
On the top navigation bar, click Resources.
From the left navigation pane, select Virtualization.
Click the Expand icon
on the left of CloudOS, and then click the Expand icon 
on the left of a cluster.
Click the name of a host.
Click Enter Maintenance Mode.
Select Automatically migrate running or suspended cloud hosts to another host or Automatically migrate shutdown cloud hosts to another host, and then click OK.
Configure a host to exit maintenance mode
On the top navigation bar, click Resources.
From the left navigation pane, select Virtualization.
Click the Expand icon
on the left of CloudOS, and then click the Expand icon 
on the left of a cluster.
Click the name of a host.
Click Exit Maintenance Mode.