[RFC] KVM snapshot support on RHEL(6.5 <= vesion < 7)

[Edison Su <Ed...@citrix.com>]

As we discussed[1][2] before, in ACS release, by default, there is no live volume snapshot for KVM, due to starting from 6.5, qemu-img can't recognize "-s", which used by CloudStack to backup snapshot.
One possible solution, to bring the function back, is to build a separate qemu-img rpm from 6.5 with "-s" support, we can name the rpm as "cloudstack-qemu-img-extra" or whatever, and make sure this rpm won't overwrite anything installed on the system, so that won't break RHEL supportability(if anybody care).
The changes we need:

1.       Build a RPM with "-s" support

2.       Push the RPM to a public repo

3.       During KVM agent installation procedure, need to install above RPM after KVM agent installed. This step can be either manually, or automatically.
Any comments on above steps?

[1] http://markmail.org/message/b57vbbvjzp5g2562
[2] http://www.nux.ro/archive/2014/01/Taking_KVM_volume_snapshots_with_Cloudstack_4_2_on_CentOS_6_5.html

Re: [RFC] KVM snapshot support on RHEL(6.5 <= vesion < 7)

[Nux! <nu...@li.nux.ro>]

On 27.02.2014 23:15, Edison Su wrote:
> As we discussed[1][2] before, in ACS release, by default, there is no
> live volume snapshot for KVM, due to starting from 6.5, qemu-img can't
> recognize "-s", which used by CloudStack to backup snapshot.
> One possible solution, to bring the function back, is to build a
> separate qemu-img rpm from 6.5 with "-s" support, we can name the rpm
> as "cloudstack-qemu-img-extra" or whatever, and make sure this rpm
> won't overwrite anything installed on the system, so that won't break
> RHEL supportability(if anybody care).
> The changes we need:
> 
> 1.       Build a RPM with "-s" support
> 
> 2.       Push the RPM to a public repo
> 
> 3.       During KVM agent installation procedure, need to install
> above RPM after KVM agent installed. This step can be either manually,
> or automatically.
> Any comments on above steps?
> 
> [1] http://markmail.org/message/b57vbbvjzp5g2562
> [2]
> http://www.nux.ro/archive/2014/01/Taking_KVM_volume_snapshots_with_Cloudstack_4_2_on_CentOS_6_5.html

To be honest I'm quite comfortable with leveraging manually the 
"cloud-qemu-img" functionality in ACS as per my blog post, of course 
large deployments can script this via ansible/puppet/etc; shipping it 
via RPM might require a bit of effort but it's doable, too.

This will not be an issue with EL7 AFAIK. I don't know what got into RH 
with this change, it also was not fair play on the oVirt people.

Lucian

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Nux!
www.nux.ro