On 10/07/2015 07:56 AM, Dr. David Alan Gilbert wrote: > * Denis V. Lunev (d...@openvz.org) wrote: >> From: Igor Redko <red...@virtuozzo.com> >> >> In this patch the ability to start a migration with test-only >> capability was added. It allows to gather the guest VM’s memory >> usage statistics avoiding time and memory overheads and real >> data transmission. New MIGRATION_STATUS_TEST_COMPLETED was >> added to distinguish between test migration and true migration >> success states. > > Why isn't this just a new transport? i.e. I could do this just by doing > a migrate to test: ? > > It seems simpler and avoids some of the special casing?
Indeed. Even if the new state can only be triggered by using a new
option, the fact that the new state exists in introspection means
clients have to figure out what to do with it; while a new transport
would not require any new states ("running" to completion means that
nothing migrated, but the existing states can then be reused to see that
the test: transport has finished computing its numbers).
>> +++ b/qapi-schema.json
>> @@ -432,6 +432,8 @@
>> #
>> # @completed: migration is finished.
>> #
>> +# @test-completed: migration time estimation finished.
>> +#
If this gets added, in spite of our ideas to use a 'test:' transport
instead of a new state, it would need a 'since 2.5' marker.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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