[ovirt-users] Local storage with self-hosted mode

[Jason Greene]

Thanks for the suggestions.

Following Maor’s suggestion I was able to add a local domain, but that required maintenance mode, so I had to failure the engine over to another host to  make the change to the current host. 

I like the appliance solution a little better, although I think it’s best if I were to run it under its own private KVM process unmanaged by ovirt, so that its possible to edit and cycle the host. Unfortunately it’s still a bit cumbersome as you need to have an engine appliance per system or shuffle around the image with some sort of disaster recovery plan.

I also looked into using gluster or cephfs as a way to share state, but noticed the BZs about the lack of complete atomicity leading to duplicate engines.

This is probably not the right place for dev musings, but IMO it would be great if in a future release there could be a solution that doesn’t require shared storage, which for smaller use-cases is often too pricey of a requirement. Ideally, under such a “horizontal” setup, each host could govern its own management data, and the engine could act more as an authoritative aggregator, thereby reducing the need for ha (if it fails just reinstall a clean one and let it reimport everything). It seems like most of the pieces are already there, with the per host-vdsm instance already containing much of the data. I’m guessing the missing element is having the engine support pulling that information as opposed to just pushing it. This is sort of like a capability that an unnamed proprietary competitor has, so it might have some sort of appeal. Of course such setups do have limitations, like you still need shared storage for live migrations and so on. So I certainly understand the rational behind the existing design. Anyway it’s just some food for thought.

Thanks

-Jason

> On Dec 7, 2014, at 6:26 AM, Doron Fediuck <dfediuck at redhat.com> wrote:
> 
> Hi Jason,
> Hosted Engine was designed to work with a shared storage since all hosts
> need to share information on their status, and by that support high-availability
> for this VM.
> 
> If you do not need high-availability you can use RHEV appliance to get a VM
> running with the engine inside. Remember that failure of this host will kill
> the engine VM as well.
> 
> Doron
> 
> ----- Original Message -----
>> From: "Maor Lipchuk" <mlipchuk at redhat.com>
>> To: "Jason Greene" <jason.greene at redhat.com>
>> Cc: users at ovirt.org
>> Sent: Sunday, December 7, 2014 1:22:44 PM
>> Subject: Re: [ovirt-users] Local storage with self-hosted mode
>> 
>> Hi Jason,
>> 
>> Did you try to create a new local Data Center, and add a local storage domain
>> there?
>> or it have to be on the same Data Center containing the hosted engine?
>> 
>> Regards,
>> Maor
>> 
>> 
>> ----- Original Message -----
>>> From: "Jason Greene" <jason.greene at redhat.com>
>>> To: users at ovirt.org
>>> Sent: Friday, December 5, 2014 11:20:31 PM
>>> Subject: [ovirt-users] Local storage with self-hosted mode
>>> 
>>> 
>>> Is there any way to use local storage with self-hosted mode for VMs other
>>> than the engine? The interface does not seem to allow it. I can hack in
>>> local storage on vdsm, but its not discovered/used by the engine (so i
>>> assume this is because it keeps its own metadata). I tried using a posix
>>> domain but there seems to be an expectation that the posix domain is
>>> accessible to all other hosts.
>>> 
>>> My use case is 2 physical servers with no shared storage options, and we
>>> need
>>> fast I/O since the VMs are used for CI, so local storage is the ideal
>>> setup.
>>> 
>>> -Jason
>>> _______________________________________________
>>> Users mailing list
>>> Users at ovirt.org
>>> http://lists.ovirt.org/mailman/listinfo/users
>>> 
>> _______________________________________________
>> Users mailing list
>> Users at ovirt.org
>> http://lists.ovirt.org/mailman/listinfo/users
>> 

--
Jason T. Greene
WildFly Lead / JBoss EAP Platform Architect
JBoss, a division of Red Hat