Cells: Broadcast call messages fail if a child cell goes down

[Sam Morrison]

If a child cell stops functioning we still include it when we send down broadcast messages that require a response.
This causes things like listing hosts, hypervisor-stats etc. to fail if one of your compute cells is down.

We know if the cell is mute so we shouldn't send messages to it and expect replies while it's in this state.

[Sam Morrison (sorrison)]

https://review.openstack.org/90589

[Chris Behrens (cbehrens)]

But I think you want it to fail. You really should not return a partial response from the API. It should be all or nothing. (Or, there needs to be some way to say "Hey, here's what I know, but there's some data missing because cell 'x' is mute".)

[Sam Morrison (sorrison)]

OK I guess we could raise a CellTimout straight away if a cell was mute instead of waiting for it to timeout (default 60s )

I'm still a bit torn, I agree with you but it would be nice if when one cell went down it wouldn't cause things to fail when information from that cell might not be wanted.

Things like the ability of taking a cell down for maintenance would be great, currently it's not possible.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Sam Morrison (<email address hidden>) on branch: master
Review: https://review.openstack.org/90589
Reason: Not the right way to do this. Need another approach

[Sean Dague (sdague)]

Low priority as cells remains experimental in the codebase

[Markus Zoeller (markus_z) (mzoeller)]

This is an automated cleanup. This bug report has been closed because it
is older than 18 months and there is no open code change to fix this.
After this time it is unlikely that the circumstances which lead to
the observed issue can be reproduced.

If you can reproduce the bug, please:
* reopen the bug report (set to status "New")
* AND add the detailed steps to reproduce the issue (if applicable)
* AND leave a comment "CONFIRMED FOR: <RELEASE_NAME>"
  Only still supported release names are valid (LIBERTY, MITAKA, OCATA, NEWTON).
  Valid example: CONFIRMED FOR: LIBERTY