libvirt disk.config will have issues when booting two with different config drive values

[Solly Ross]

Currently, in the image creating code for Juno we have

        if configdrive.required_by(instance):
            LOG.info(_LI('Using config drive'), instance=instance)

            image_type = self._get_configdrive_image_type()
            backend = image('disk.config', image_type)
            backend.cache(fetch_func=self._create_configdrive,
                          filename='disk.config' + suffix,
                          instance=instance,
                          admin_pass=admin_pass,
                          files=files,
                          network_info=network_info)

The important thing to notice here is that we have "filename='disk.confg' + suffix". This means that the filename for the config drive in the cache directory will be simply 'disk.config' followed by any potential suffix (e.g. '.rescue'). This name is not unique to the instance whose config drive we are creating. Therefore, when we go to boot another instance with a different config drive, the cache function will detect the old config drive, and decide it doesn't need to create the new config drive with the appropriate config for the new instance.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/121604

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/123073

[Michael Still (mikal)]

In the end it looks like we're resolving this one by reverting these changes:

  228d0221763b12f11ecbacde4db38b1151f96e31
  0b01e846d40f3b343da9ebe1dae89cca8bc2ac66
  ecce888c469c62374a3cc43e3cede11d8aa1e799

[Jeremy Stanley (fungi)]

This only affects juno right? (Those changes are only in the master branch?) Just confirming we don't need an advisory for any released versions.

[Solly Ross (sross-7)]

Yep, it's only people running off of master.

[Jeremy Stanley (fungi)]

Thanks Solly. Setting the OSSA task to won't fix in that case, to track that we don't need an advisory.

[Michael Still (mikal)]

These reverts have now merged.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Sean Dague (<email address hidden>) on branch: master
Review: https://review.openstack.org/121604
Reason: This review is > 4 weeks without comment and currently blocked by a core reviewer with a -2. We are abandoning this for now. Feel free to reactivate the review by pressing the restore button and contacting the reviewer with the -2 on this review to ensure you address their concerns.

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/159087

[OpenStack Infra (hudson-openstack)]

Change abandoned by Mehdi Abaakouk (<email address hidden>) on branch: master
Review: https://review.openstack.org/159087
Reason: Merged in previous review

[OpenStack Infra (hudson-openstack)]

Change abandoned by Joe Gordon (<email address hidden>) on branch: master
Review: https://review.openstack.org/123073
Reason: This review is > 4 weeks without comment, and failed Jenkins the last time it was checked. We are abandoning this for now. Feel free to reactivate the review by pressing the restore button and leaving a 'recheck' comment to get fresh test results.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/123073
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=adecf780d3ed4315e4ce305cb1821d493650494b
Submitter: Jenkins
Branch: master

commit adecf780d3ed4315e4ce305cb1821d493650494b
Author: Michael Still <email address hidden>
Date: Tue Nov 25 15:42:47 2014 +0300

    Handle config drives being stored on rbd

    rbd is the only example of a currently supported image storage
    backend where it makes sense to put the config drive in the
    configured storage backend instead of local hypervisor disk. I
    don't think this makes sense for LVM, where we would be creating
    a LV for a tens of megabytes file, which seems like overkill to
    me. The other storage backends use local disk for their data
    already.

    This use case was covered by the now reverted changes:
      228d0221763b12f11ecbacde4db38b1151f96e31
      0b01e846d40f3b343da9ebe1dae89cca8bc2ac66
      ecce888c469c62374a3cc43e3cede11d8aa1e799

    Support this special case by moving the image to rbd once it has
    been created in the local instance directory on the hypervisor.

    I've tested this change in devstack and it works.

    Related-bug: #1369627
    Related-bug: #1361840
    Related-bug: #1246201

    Co-Authored-By: Mehdi Abaakouk <email address hidden>
    Co-Authored-By: Dan Smith <email address hidden>

    Change-Id: Ia3ca5a18c79d62b71b9c042a612d12dd074b245e

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: stable/kilo
Review: https://review.openstack.org/214773

[OpenStack Infra (hudson-openstack)]

Change abandoned by Rosario Di Somma (<email address hidden>) on branch: stable/kilo
Review: https://review.openstack.org/214773