[ovirt-devel] DRBD Integration with oVirt

[Hayley Swimelar]

On 06/06/2016 11:02 AM, Yaniv Kaul wrote:
> On Mon, Jun 6, 2016 at 7:23 PM, Hayley Swimelar <hayley at linbit.com> wrote:
>
>>
>>
>> On 06/04/2016 10:40 PM, Barak Korren wrote:
>>
>>>
>>>> We are looking for advice on how best to have oVirt communicate with DRBD
>>>> Manage and we have come to two options:
>>>>
>>>>
>>> My vote would be for native support rather then a Cinder based one. I
>>> don't have any hard numbers, but it seems to me the adoption of
>>> OpenStack technologies for use with oVirt is not as widespread as one
>>> may hope.
>>>
>>> But what sort of user experience and system architecture is intended?
>>> Is configuration of volumes planned to be done directly from the oVirt
>>> UI?
>>>
>>
>> Once a DRBD Manage storage cluster is set up, oVirt would handle the
>> management of DRBD volumes.
>>
>> While oVirt can do a little Gluster volume management for now, it
>>> seems it was done because it some point it was thought that oVirt
>>> would be the primary management UI for Gluster. AFAIK Gluster is now
>>> getting its own UI.
>>>
>>
>> The DRBD Manage daemon ships with a command line utility which is the UI
>> for interacting with DRBD 9. I do not believe that there is a stand alone
>> DRBD GUI planned at this time.
>>
>
> Is using the CLI considered a 'stable API' ? (or perhaps it can output a
> JSON or something that can be considered as such)?
>

oVirt wouldn't use the CLI, it would talk directly to the underlying 
DRBD Manage process (drbdmanaged) via D-Bus.

As far as setting up the cluster initially, the DRBD Manage client (CLI) 
is designed to be used by the end user, so it's pretty user-friendly.

>
>> At least for now, the user most likely will prepare a DRBD Manage cluster
>> up to the point where it's ready to start creating/assigning volumes and
>> then oVirt will take over from there.
>>
>> As far as using DRBD for backing oVirt VMs, this seems to already be
>>> working. The oVirt CI system (which runs on top of oVirt) had been
>>> using a DRBD-backed NFS storage for years...
>>>
>>>
>> The most recent release of DRBD contains new features that allow it to
>> integrate more directly with virtualization/cloud platforms. So VMs could
>> have DRBD-backed storage without additional overhead from NFS.
>
>
> Via RADOS pools?

The DRBD devices would be attached over the network, similar to the way 
they are in Cinder: 
https://www.drbd.org/en/doc/users-guide-90/s-openstack-transport-protocol


>
>>
>>
>> --
>> Hayley Swimelar
>> LINBIT | Keeping the Digital World Running
>> DRBD — Corosync — Pacemaker
>> +1-503-573-1262 x212
>> _______________________________________________
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>> Devel at ovirt.org
>> http://lists.ovirt.org/mailman/listinfo/devel
>>
>

-- 
Hayley Swimelar
LINBIT | Keeping the Digital World Running
DRBD — Corosync — Pacemaker
+1-503-573-1262 x212