Image "container_format" incorrectly modified when editing image

[Alex Oughton]

Hello,

When editing a Glance image in Horizon (for example, changing its name), Horizon is incorrectly changing the container_format to "bare", losing whatever the value previously was. This is affecting images which have been taken from XenServer, as the container_format is changed from "ovf" to "bare". The end-result of this, is that Cinder does not run through the proper image conversion procedures (coalesce, etc.) when creating a Volume from that Image. Instead it will just dump the .gz file onto the volume, which is obviously unbootable.

We have traced the problem down to the file /usr/share/openstack-dashboard/openstack_dashboard/dashboards/project/images/images/forms.py. In the function "create_image_metadata", there is a section which states:

if disk_format in ('ami', 'aki', 'ari',):
    container_format = disk_format
elif disk_format == 'docker':
    # To support docker containers we allow the user to specify
    # 'docker' as the format. In that case we really want to use
    # 'raw' as the disk format and 'docker' as the container format.
    disk_format = 'raw'
    container_format = 'docker'
else:
    container_format = 'bare'

It's clear to see here how this is overriding the container_format from its proper value. I believe an appropriate patch would be to add an an "elif disk_format=='vhd' " section. For example, we have done the following which is working for us:

if disk_format in ('ami', 'aki', 'ari',):
    container_format = disk_format
elif disk_format == 'docker':
    # To support docker containers we allow the user to specify
    # 'docker' as the format. In that case we really want to use
    # 'raw' as the disk format and 'docker' as the container format.
    disk_format = 'raw'
    container_format = 'docker'
elif disk_format == 'vhd':
    container_format = 'ovf'
else:
    container_format = 'bare'

I'm not enough of a developer to know if this is truly the correct patch, or if this will break some other functionality for someone else. Could a real developer please take a look at this, and patch as appropriate?

Thanks in advance,

Alex Oughton

[Renjie Sun (sunrenjie6)]

I took a cirros qcow2 image, convert to vhd (using qemu-img command given in [1]), upload with container_format=ovf to a devstack+kvm installation to give it a run.

The part of modifying container_format to bare while editing the image is verified, as expected. However, the vhd image with bare container_format can be used to boot vm (maybe some kvm vs. Xen thing?). Therefore, there is no strong reason to give a disk=vhd => container=ovf deduction (correct me if possible). Anyway, the inline comments and docs [2] do not say much about that.

That said, the idea I come up is that, we could take the existing container value into account in create_image_metadata(). If the image format does not change during the image update, we could re-use the old container_format. Otherwise, we shall fall back to the existing deduction logic. Such modest approach may fit horizon better, being a client as thin as possible.

I created a quick-and-dirty patch for it. Please take a look at it. :)

[1] http://docs.openstack.org/image-guide/convert-images.html
[2] http://docs.openstack.org/image-guide/image-formats.html

[Alex Oughton (alex-oughton)]

Hello Renjie,

Thank you for taking a look at this. The loss of the container_format value is an issue when using Boot from Volume with XenServer. This is because Cinder only performs the proper image conversion processes for a XenServer image when the container_format is set to OVF.

Correct procedure when container_format set to "OVF": Cinder will extract the tgz image file, use vhd-util to coalesce the VHD files together, and then use qemu-img to dump the coalesced VHD to a volume. This is then bootable.

Incorrect procedure when container_format set to "Bare": Cinder will dump the tgz file directly onto the volume. This is obviously not bootable.

I hope this helps explain the issue a little better. Thanks again for looking into this already.

Alex Oughton

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/275482

[Renjie Sun (sunrenjie6)]

Hello, Alex,

Thanks for the clarification.
The patch is proposed as the Infra robot already posted. Feel free to comment on that.
The fix is really ad-hoc. Hopefully there will be a better approach, or even a solution in glance's part.

[Alex Oughton (alex-oughton)]

Hello Renjie,

I applied your patch to my system (rolling-back the other changes I had made), and found it to work. The "OVF" value was retained as desired.

Thanks,

Alex Oughton

[OpenStack Infra (hudson-openstack)]

Change abandoned by Rob Cresswell (<email address hidden>) on branch: master
Review: https://review.openstack.org/275482
Reason: Abandoned due to inactivity

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/664132
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=ba75bafc69c03f04b3c7d4f50e1cc9e3123743a3
Submitter: Zuul
Branch: master

commit ba75bafc69c03f04b3c7d4f50e1cc9e3123743a3
Author: 白子玉 <email address hidden>
Date: Sat Jun 8 15:14:51 2019 +0800

    Specify proper container_format for 'vhd' disk_format

    When editing an image, if the disk_fomrat is 'vhd',
    the container_format was wrongly set to 'bare' before.
    'ovf' is the correct container_format for 'vhd' disk images.

    Closes-Bug: #1539722
    Change-Id: Ic6b0c66af0d5c8db2d802d6eea2b97721d92b7eb

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/horizon 16.0.0.0rc1 release candidate.