[one-users] Architecture advice

[Stuart Longland]

On 18/03/14 02:35, Gandalf Corvotempesta wrote:
> Hi to all
> i'm planning a brand new cloud infrastructure with opennebula.
> I'll have many KVM nodes and 3 "management nodes" where I would like
> to place OpenNebula, Sunstone and something else used to orchestrate
> the whole infrastructure
> 
> Simple question: can I use these 3 nodes to power on OpenNebula (in
> HA-Configuration) and also host some virtual machines managed by
> OpenNebula ?

I could be wrong, I'm new to OpenNebula myself, but from what I've seen,
the management node isn't a particularly heavyweight process.

I had it running semi-successfully on an old server here (pre
virtualisation-technology).  I say semi-successfully; the machine had a
SCSI RAID card that took a dislike to Ubuntu 12.04, so the machine I had
as the master would die after 8 hours.

I was using SSH based transfers (so no shared storage) at the time.

Despite this, the VMs held up, they just couldn't be managed.  This
won't be the case if your VM hosts mount any space off the frontend
node: in which case a true HA set-up is needed.  (And lets face it, I
wouldn't recommend running the master node as a VM if you're going to be
mounting storage directly off it for the hosts.)

Based on this it would seem you could do a HA setup with some shared
storage between the nodes, either a common SAN or DR:BD to handle the
OpenNebula frontend.

Seeing as OpenNebula will want to control libvirt on the hosts (being
that you're also suggesting making these run the OpenNebula-managed VMs
too, this might have to be a KVM process managed outside of libvirt.
Not overly difficult, just fiddly.

But, as I say, I could be wrong, so take the above advice with a grain
of salt.

Regards,
-- 
Stuart Longland
Systems Engineer
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