The most disruptive action that you want to perform on each
instance during the update: - REPLACE: Delete the instance and
create it again. - RESTART: Stop the instance and start it
again. - REFRESH: Do not stop the instance. - NONE: Do not
disrupt the instance at all. By default, the most disruptive
allowed action is REPLACE. If your update requires a more
disruptive action than you set with this flag, the update
request will fail. Additional supported values which may be not
listed in the enum directly due to technical reasons: NONE
REFRESH
REPLACE
RESTART
Values:
UNDEFINED_MOST_DISRUPTIVE_ALLOWED_ACTION (0):
A value indicating that the enum field is not
set.