[FakeDriver] Live migration issue, power_state=NOSTATE

[Lorenzo Affetti]

[nova master]
In FakeDrivers, when live-migrating an instance everything goes ok.
So, resources are allocated the correct way and instance's host has been changed, but instance Power State goes to NOSTATE.

This seems to be caused by get_info method which programmatically raises InstanceNotFound exception.
Instances list inside FakeDriver seems not to be updated accordingly.

I actually fixed the problem in my local code (nova.virt.fake.FakeDriver) with:

def live_migration(self, context, instance, dest,
                       post_method, recover_method, block_migration=False,
                       migrate_data=None):
        post_method(context, instance, dest, block_migration,
                            migrate_data)

++ name = instance['name']
++ del self.instances[name]

        return

and

def post_live_migration_at_destination(self, context, instance,
                                           network_info,
                                           block_migration=False,
                                           block_device_info=None):

++ name = instance['name']
++ state = power_state.RUNNING
++ fake_instance = FakeInstance(name, state, instance['uuid'])
++ self.instances[name] = fake_instance

But I don't know if it is a satisfying solution.
With this solution the instance is live_migrated and in state ACTIVE and power state RUNNING after the operation.

Thank you

[Davanum Srinivas (DIMS) (dims-v)]

Lorenzo, will you be filing a review?
https://wiki.openstack.org/wiki/How_To_Contribute

[Lorenzo Affetti (affox90)]

O yes, I think I will do it asap.
I think that my solution is a nitty gritty one and i hoped to find experts to write a more suitable code!
I have never bugfixed something.

I will try with pleasure.

[Andrea Rosa (andrea-rosa-m)]

@Lorenzo are you still working on this bug? If not please change the assignee from you to 'nobody'

[Lorenzo Affetti (affox90)]

@Andrea thank you for waking me up! I want to fix this in next weeks.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/243613

[Anup (anup-d-navare)]

Is this bug fixed?

[Markus Zoeller (markus_z) (mzoeller)]

The age of this report and number of assignee changes suggest that this
isn't really a low-hanging-fruit. I'm removing the tag to not confuse
new folks who are searching for that tag.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Michael Still (<email address hidden>) on branch: master
Review: https://review.openstack.org/243613
Reason: This patch is quite old, so I am abandoning it to keep the review queue manageable. Feel free to restore the change if you're still interested in working on it.

[Matt Riedemann (mriedem)]

I think this might be resolved in a few forms now:

https://github.com/openstack/nova/commit/67f1c98898406d2c663f46e6380762d81f38aff9

https://github.com/openstack/nova/commit/87ca0d8af0d6440a7effd4da9e47321b3a335442

https://github.com/openstack/nova/commit/ce893e37fa032b9dceddc221ed336eb89e6eb880

If not, I had to do something similar for cold migration testing across different hosts:

https://github.com/openstack/nova/commit/dc5c69d0d118be838245a18fb636b044249a9863

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/243613
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=14342d629b714f172545f133314b5ce584503cae
Submitter: Zuul
Branch: master

commit 14342d629b714f172545f133314b5ce584503cae
Author: Lorenzo Affetti <email address hidden>
Date: Tue Nov 10 12:56:59 2015 +0100

    FakeDriver: adding and removing instances on live migration.

    There was no code in FakeDriver that updated the internal
    dict `self.instances` when a FakeInstance was live migrated.
    This commit fills this gap. As a result, a couple of versioned
    notification samples get updated since we are now properly
    tracking a live migrated instance on the destination host as
    running vs pending power state.

    Closes-Bug: 1426433

    Change-Id: I9562e1bcbb18c7d543d5a6b36011fa28c13dfa79