[ovirt-devel] DRBD Integration with oVirt

[Federico Simoncelli]

Hi Hayley.

In the past I developed a POC for DRBD in oVirt.

  https://gerrit.ovirt.org/#/c/13585/

It's quite old and things have changed so for sure it's not up to
date. It also took some assumptions that may different from what you
want to achieve.

In fact it assumed to be hyper-converged which, at that time, it meant
that only data-centers of two nodes were supported (maybe DRBD changed
in this respect now, I remember there were some plans around this
circa 2014).
The idea was to achieve HA in small deployment of few VMs (e.g. ROBO).

On the other hand in case you want to separate compute and storage
then you could deploy DRBD on two hosts (outside of the oVirt
clusters) and expose the block device using iscsi (active/passive or
active/active with multipath).
I haven't checked what Cinder does, maybe it's something similar to
what I described here above.

Anyway that would work today out-of-the-box with no modifications to
oVirt, but of course has some complexities in deployment, testing and
maintenance (and hopefully a negligible performance penalty).

I don't know what are the general directions nowadays but in the past
(regardless of the architecture) I would have suggested to use VDSM as
agent to setup the DRBD storage.
(Anyway provisioning would come after you picked the architecture).

Thanks,

On Fri, Jun 3, 2016 at 8:13 PM, Hayley Swimelar <hayley at linbit.com> wrote:
> Hello all,
>
> A DRBD integration into oVirt is currently being planned.
>
> DRBD provides replicated, highly available block storage. For those
> unfamiliar with DRBD more information can be found here:
> https://www.drbd.org/en/comp/drbd-linux-driver
>
> DRBD 9 is the latest version of DRBD and interacts with DRBD Manage which is
> a daemon exposed via a D-Bus api. More information can be found here:
> https://www.drbd.org/en/comp/drbdmanage
>
> DRBD Manage handles the creation, assignment, etc. of DRBD volumes and is
> the interface through which Cinder manages DRBD.
>
> We are looking for advice on how best to have oVirt communicate with DRBD
> Manage and we have come to two options:
>
> 1) Use Cinder. Although we are integrated into Cinder, there are concerns
> about the need to set up a complete Cinder instance to provide access to
> DRBD.
>
> 2) The alternative to Cinder would be to have the oVirt Engine communicate
> directly to DRBD Manage via D-Bus.
>
> Any advice on the best way to achieve this would be much appreciated.
>
> --
> Hayley Swimelar
> LINBIT | Keeping the Digital World Running
> DRBD — Corosync — Pacemaker
> +1-503-573-1262 x212
> _______________________________________________
> Devel mailing list
> Devel at ovirt.org
> http://lists.ovirt.org/mailman/listinfo/devel

-- 
Federico