Kernel zone evacuation is the process of live migrating all the running kernel zones off a system at once, and optionally returning them to the system later. By live migrating all kernel zones from a host system onto other systems temporarily, you can perform maintenance on the host system without having to halt applications that are running in those kernel zones. You can optionally evacuate all zones, including kernel zones that are not running solaris zones in the installed state.
Evacuation uses the Remote Administration Daemon (RAD) to coordinate and execute the migration of zones to their destinations, so RAD services must be running on source hosts and target hosts. For more information about RAD, see the rad(8) man page.
The overall process for kernel zone evacuation is:
Ensure the requirements are met for the source and target hosts.
Set a destination host for each of the migrating kernel zones by setting an SMF service property.
Place the source host in maintenance mode to prevent non-running zones from attaching, booting, or migrating in.
Run the evacuate command to migrate the running kernel zones to their preset destination.
Go to Evacuating Kernel Zones.
Perform the system maintenance on the source host and reboot.
End the maintenance mode on the source host system.
Return the evacuated zones to the source host, if desired. Evacuation can also be used to permanently migrate zones to a new host.
The sysadm utility enables you to perform all evacuation tasks.
Use the sysadm maintain command to prepare for migration by placing the system in a maintenance mode that prevents zones from being attached, booted, or migrating in.
Use the sysadm evacuate command to perform the actual migration of zones in an evacuation operation.
See the sysadm(8) man page for complete information.
The sysadm maintain command accepts the following options:
End maintenance mode.
List the current status of maintenance mode.
Message you can specify to indicate reason for maintenance, for example.
Start maintenance mode to prevent new zones from running on the source host.
Maintenance state persists across system reboots and applies to all boot environments, so you must explicitly end the maintenance mode with the sysadm maintain -e command.
The sysadm evacuate command accepts the following options:
All zones, both non-running and running, are evacuated.
Non-executing dry run of the evacuation to show how the evacuation would be performed.
Quiet output, showing only errors.
Return the evacuated zones to the source host.
Verbose output, showing progress of the evacuation.
Overwrite zone configurations of all zones on the destination host with the respective configurations from the source host. This option is mutually exclusive with the –n option.