Evacuate instancesIf a cloud compute node fails due to a hardware malfunction
or another reason, you can evacuate instances to make them
available again.You can choose evacuation parameters for your use
case.To preserve user data on server disk, you must configure
shared storage on the target host. Also, you must validate
that the current VM host is down. Otherwise the evacuation
fails with an error.To find a different host for the evacuated instance,
run this command to list hosts:$nova host-listYou can pass the instance password to the command by
using the --password <pwd>
option. If you do not specify a password, one is
generated and printed after the command finishes
successfully. The following command evacuates a server
without shared storage:$nova evacuate evacuated_server_namehost_bThe command evacuates an instance from a down host
to a specified host. The instance is booted from a new
disk, but preserves its configuration including its
ID, name, uid, IP address, and so on. The command
returns a password:+-----------+--------------+
| Property | Value |
+-----------+--------------+
| adminPass | kRAJpErnT4xZ |
+-----------+--------------+To preserve the user disk data on the evacuated
server, deploy OpenStack Compute with shared file
system. To configure your system, see Configure migrations in
OpenStack Configuration
Reference. In this example, the
password remains unchanged.$nova evacuate evacuated_server_namehost_b --on-shared-storage