nova.cells.messaging.instance_update_at_top is assuming it gets an Instance object

[Matt Riedemann]

This code assumes that the instance parameter is a nova Instance object:

https://github.com/openstack/nova/blob/86fe90f7056432416ea3c2335ea8c2ad6e16b79a/nova/cells/messaging.py#L1020

But if you're using cells RPC API < 1.35 it's a primitive dict:

https://github.com/openstack/nova/blob/86fe90f7056432416ea3c2335ea8c2ad6e16b79a/nova/cells/rpcapi.py#L205

This was introduced with eaaa659333c7586a71155c065dfb0f7b7e3758fc in 12.0.0 (Liberty).

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/252045

[Kasey Alusi (kasey-alusi)]

Can I pick this up? Should the review above be abandoned if so?

[OpenStack Infra (hudson-openstack)]

Change abandoned by Matt Riedemann (<email address hidden>) on branch: master
Review: https://review.openstack.org/252045
Reason: Looks like this is abandoned.

[Matt Riedemann (mriedem)]

@Kasey, yeah, go for it.

[Markus Zoeller (markus_z) (mzoeller)]

@Kasey: Are you still working on this?

[Kasey Alusi (kasey-alusi)]

I totally missed the message/abandoned review. So, I have not been working on this, but I would like to.

[Kasey Alusi (kasey-alusi)]

Hey, so I have created gotten devstack up with nova-cells enabled, but I am trying to figure out how to trigger this bug/dive into how to fix it. Is there someone that may know how to trigger this? I would like to tackle this bug but am not really familiar enough with cells/the rpc api to know how to repro it. I think based on the abandoned review the fix seems simple enough, but I cant be sure that my changes actually fix this yet.

[Matt Riedemann (mriedem)]

The cells RPC API version has to be less than 1.35, see:

https://github.com/openstack/nova/blob/86fe90f7056432416ea3c2335ea8c2ad6e16b79a/nova/cells/rpcapi.py#L117

You'll have to fake this out on a single node devstack to recreate probably.

Try setting this in your nova.conf:

[upgrade_levels]
cells=kilo

Since the kilo rpc api version is 1.34.

You'll have to restart the cells service for that to take effect.

[Sivasathurappan Radhakrishnan (siva-radhakrishnan)]

 It was decided not to work on cells bugs as cells v1 is going to be deprecated and it is being planned to move to cells V2