[Users] Asking for advice on hosted engine

[Sandro Bonazzola]

Il 17/02/2014 10:20, Giorgio Bersano ha scritto:
> Hello everybody,
> I discovered oVirt a couple of months ago when I was looking for the
> best way to manage our small infrastructure. I have read any document
> I considered useful but I would like to receive advice from the many
> experts that are on this list.
> 
> I think it worths an introduction (I hope doesn't get you bored).
> 
> I work in a small local government entity and I try to manage
> effectively our limited resources.
> We have many years of experience with Linux and especially with CentOS
> which we have deployed on PC (i.e. for using as firewall in remote
> locations) and moreover on servers.
> 
> We have been using Xen virtualization from the early days of CentOS 5
> and  we have built our positive experience on KVM too.
> I have to say that libvirt in a small environment like ours is really
> a nice tool.
> So nothing to regret.
> 
> Trying to go a little further, as already said, I stumbled upon oVirt
> and I've found the project intriguing.
> 
> At the moment we are thinking of deploying it on a small environment
> of four very similar servers each having:
> - a couple of Xeon E5504
> - 6 x 1Gb ethernet interfaces
> - 40 GB of RAM
> two of them have 72 GB of disk (mirrored)
> two of them have almost 500GB of useful RAID array
> 
> Moreover we have an HP iSCSI storage that should easily satisfy our
> current storage requirement.
> 
> So, given our small server pool, the necessity of another host just to
> run the supervisor seems a requirement too high.
> 
> Enter "hosted engine" and the picture takes brighter colors. Well, I'm
> usually not the adventurous guy but after experimenting a little with
> oVirt 3.4 I developed better confidence.
> We would want to install the engine over the two hosts with smaller disks.
> 
> For what I know, installing hosted engine mandates NFS storage. But we
> want this to be highly available too, and possibly to have it on the
> very same hosts.
> 
> Here is my solution: make a gluster replicated volume across the two
> hosts and take advantage of that NFS server.
> Then I put 127.0.0.1 as the address of the NFS server in the
> hosted-engine-setup so  the host is always able to reach the storage
> server (itself).
> GlusterFS configuration is done outside of oVirt that, regarding
> engine's storage, doesn't even know that it's a gluster thing.
> 
> Relax, we've finally reached the point where I'm asking advice :-)
> 
> Storage and virtualization experts, do you see in this configuration
> any pitfall that I've overlooked given my inexperience in oVirt,
> Gluster, NFS or clustered filesystems?
> Do you think that not only it's feasable (I know it is, I made it and
> it's working now) but it's also reliable and dependable and I'm not
> risking my neck on this setup?

I'm not sure about how reliable may be the sanlock protection of the hosted engine image over a gluster volume.
Maybe Federico can tell you more about this.


> 
> I've obviously made some test but I'm not at the confidence level of
> saying that all is right in the way it is designed.
> 
> OK, I think I've already written too much, better I stop and humbly
> wait for your opinion but I'm obviously here if any clarification by
> my part  is needed.
> 
> Thank you very much for reading until this point.
> Best Regards,
> Giorgio.
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> 


-- 
Sandro Bonazzola
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