ESX: Entering maintainance mode via command line

To enter Maintenance Mode, at the ESX console type:

vimsh -n -e /hostsvc/maintenance_mode_enter

To exit Maintenance Mode type:

vimsh -n -e /hostsvc/maintenance_mode_exit

To display whether the ESX Server is currently in maintenance mode or not type:

vimsh -n -e"hostsvc/hostsummary" | grep inMaintenanceMode