Don't detach root device volume

[OpenStack Infra]

https://review.openstack.org/75552
commit 7fbb42296970ee30d21bbd66b144a2ab421aa17f
Author: Yunhong Jiang <email address hidden>
Date: Fri Feb 21 18:11:03 2014 -0800

    Don't detach root device volume

    Detach a root device volume may cause various guest error. Although
    we can argue that it's user response to not detach the root device
    volume, a check in nova will be more helpful.

    We can either give a warning message, or not allow it. This patch
    forbids this operation, considering that even in real system, remove
    root device does not make much sense.

    Closes-Bug: #1279300

    DocImpact

    Change-Id: I01f086be668b35442a2f139f4d7dc96884a3bda6
    Signed-off-by: Yunhong Jiang <email address hidden>

[Tom Fifield (fifieldt)]

This is welcome behaviour.

However, the new return codes need to be documented in api-site.

To solve this bug, add the new return codes and an explanation of when they occur to the right place in the compute api doc

[Schad (ubuntu-20-schad)]

I object this being a bug. There are valid use cases where you would detach or attach a different root volume while keeping the VM.

[Schad (ubuntu-20-schad)]

"root device does not make much sense" is an opinion only. I am affected by the correction because I need to detach the root volume from VMs.

[Tom Fifield (fifieldt)]

@Schad - this is a documentation bug, the functionality mentioned in the report has already changed in the code. If you think this was a mistake, please open a bug in https://bugs.launchpad.net/nova , referencing this link https://review.openstack.org/75552

[Diane Fleming (diane-fleming)]

https://review.openstack.org/185243

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/185243
Committed: https://git.openstack.org/cgit/openstack/api-site/commit/?id=a4262001bc6af1ea88ad18843a8d954d6bd9a467
Submitter: Jenkins
Branch: master

commit a4262001bc6af1ea88ad18843a8d954d6bd9a467
Author: Diane Fleming <email address hidden>
Date: Sat May 23 15:19:28 2015 -0500

    Cannot delete a root device volume

    Change-Id: I163a6409ee063ee0e7ea489372d9129cb9ff0012
    Closes-Bug: #1293695