[openstack-dev] [nova] nova backup not working in stable/icehouse?

Preston L. Bannister preston at bannister.us
Sat Aug 30 05:14:13 UTC 2014


The current "backup" APIs in OpenStack do not really make sense (and
apparently do not work ... which perhaps says something about usage and
usability). So in that sense, they could be removed.

Wrote out a bit as to what is needed:
http://bannister.us/weblog/2014/08/21/cloud-application-backup-and-openstack/

At the same time, to do efficient backup at cloud scale, OpenStack is
missing a few primitives needed for backup. We need to be able to quiesce
instances, and collect changed-block lists, across hypervisors and
filesystems. There is some relevant work in this area - for example:

https://wiki.openstack.org/wiki/Nova/InstanceLevelSnapshots

Switching hats - as a cloud developer, on AWS there is excellent current
means of backup-through-snapshots, which is very quick and is charged based
on changed-blocks. (The performance and cost both reflect use of
changed-block tracking underneath.)

If OpenStack completely lacks any equivalent API, then the platform is less
competitive.

Are you thinking about backup as performed by the cloud infrastructure
folk, or as a service used by cloud developers in deployed applications?
The first might do behind-the-scenes backups. The second needs an API.




On Fri, Aug 29, 2014 at 11:16 AM, Jay Pipes <jaypipes at gmail.com> wrote:

> On 08/29/2014 02:48 AM, Preston L. Bannister wrote:
>
>> Looking to put a proper implementation of instance backup into
>> OpenStack. Started by writing a simple set of baseline tests and running
>> against the stable/icehouse branch. They failed!
>>
>> https://github.com/dreadedhill-work/openstack-backup-scripts
>>
>> Scripts and configuration are in the above. Simple tests.
>>
>> At first I assumed there was a configuration error in my Devstack ...
>> but at this point I believe the errors are in fact in OpenStack. (Also I
>> have rather more colorful things to say about what is and is not logged.)
>>
>> Try to backup bootable Cinder volumes attached to instances ... and all
>> fail. Try to backup instances booted from images, and all-but-one fail
>> (without logged errors, so far as I see).
>>
>> Was concerned about preserving existing behaviour (as I am currently
>> hacking the Nova backup API), but ... if the existing is badly broken,
>> this may not be a concern. (Makes my job a bit simpler.)
>>
>> If someone is using "nova backup" successfully (more than one backup at
>> a time), I *would* rather like to know!
>>
>> Anyone with different experience?
>>
>
> IMO, the create_backup API extension should be removed from the Compute
> API. It's completely unnecessary and backups should be the purview of
> external (to Nova) scripts or configuration management modules. This API
> extension is essentially trying to be a Cloud Cron, which is inappropriate
> for the Compute API, IMO.
>
> -jay
>
>
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