simple_cell_setup reports "exiting" when it is not

[Chris Dent]

When running 'nova-manage simple_cell_setup ...' if hosts are already the _map_cell_and_hosts method prints a message of 'All hosts are already mapped to cell(s), exiting.' and then proceeds to map instances. It does not, in fact, exit.

This isn't the end of the world, but is somewhat confusing.

The easiest fix is probably to get rid of ', exiting'. Then in the multiple paths to the method, the printed message still makes sense and 'exiting' can be implicit.

[Chris Dent (cdent)]

This true from master at least back to queens.

[melanie witt (melwitt)]

Looking at the code, I can see why this happens:

        cell_uuid = self._map_cell_and_hosts(transport_url)
        if cell_uuid is None:
            # There are no compute hosts which means no cell_mapping was
            # created. This should also mean that there are no instances.
            return 1
        self.map_instances(cell_uuid)

When it says 'exiting', it's exiting the _map_cell_and_hosts method, not the simple_cell_setup method. So it will go ahead and map_instances afterward.

Agreed the message should just be updated to remove confusion.

[melanie witt (melwitt)]

To be clear, in the 'All hosts are already mapped to cell(s)' case, cell_mapping_uuid is returned from the _map_cell_and_hosts method, which will not cause simple_cell_setup to exit if it is not None.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/649340

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/649340
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=8ab3300d5d588f169b40ca7dbc6cd63370226066
Submitter: Zuul
Branch: master

commit 8ab3300d5d588f169b40ca7dbc6cd63370226066
Author: Chris Dent <email address hidden>
Date: Tue Apr 2 15:07:45 2019 +0100

    Don't report 'exiting' when mapping cells

    When running 'nova-manage simple_cell_setup...' if there are not hosts
    to map, but there remaining instances to map, an '..., exiting' message
    is produced. This is misleading because "exiting" implies a return of
    control to the user. That doesn't happen if there are many instances
    left to inspect or map.

    This change gets around that by getting rid of the exiting message
    in the case where instance mapping can still happen.

    Change-Id: I62b20a3676429b5cc756884275138566785b347e
    Closes-Bug: #1821737

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/nova 20.0.0.0rc1 release candidate.