[Pacemaker] Searching for a viable Debian solution

[Florian Haas]

Paul,

I am copying your message over to the Debian HA maintainers' mailing
list. Chances are that one of those guys can share some valuable insight.

Debian maintainers, when you respond would you mind copying the
Pacemaker list?

Cheers,
Florian

On 04/24/2010 06:01 AM, Paul Gear wrote:
> Hi folks,
> 
> Over the last several days i've been reading, asking questions (special
> thanks to beekhof, tserong, fghass and the other kind folks on #linux-ha
> putting up with my questions), and experimenting with my test setup, and
> i'm yet to find a viable combination of options for creating a VM
> cluster on Debian.
> 
> The preferred components of my setup are:
> - Debian lenny
> - Xen VMs
> - OCFS2 on an iSCSI NAS for shared storage
> - whatever openais/corosync/pacemaker combination will do the job
> - I'd like to have live migration of VMs but it's not essential
> 
> The point of my setup is to have a test cluster with which i can play
> (and run my own home network) without breaking the ones i have to
> support at customers.  I work with small businesses, educational
> institutions, and non-profits, none of whom have the means to support a
> fully working test configuration, or to buy time from big name
> consultants who can employ full-time clustering specialists.
> 
> My experiments thus far have been with corosync & pacemaker from
> http://people.debian.org/~madkiss/ha/, and with libvirt from
> lenny-backports.
> 
> When i tried the latest versions of corosync & pacemaker in the above
> repo, i was able to get the cluster running appropriately, but when i
> tried to add the DLM clone resource, i got this error: "controld[3526]:
> ERROR: Setup problem: Couldn't find utility dlm_controld.pcmk".  So it
> seems that OCFS2 is not viable with the current state of the
> corosync/openais/pacemaker stack.  I've investigated a couple of
> alternatives to my preferred list, including:
> 
> - cLVM - requires the Red Hat cluster stack and conflicts with the
> current corosync/openais/pacemaker versions.  This would be my preferred
> solution if it were possible to use LVs from the same VG on different
> nodes simultaneously.  I'm not sure whether this is possible, because
> the cLVM documentation is almost non-existent, and i couldn't find
> answers to any of my big questions.
> 
> - libvirt with iSCSI as the backend for the storage pool.  I've tried
> this and it looks promising, but it appears non-functional on iSCSI
> storage backends at the moment.  I get this message when i try to create
> a volume: "libvirtd: ... error : storageVolumeCreateXML:1301 : this
> function is not supported by the hypervisor: storage pool does not
> support volume creation"
> 
> I substituted KVM for Xen, and the result was the same.
> 
> So, the question remains: what is a viable HA stack for Debian with
> virtualization and shared storage?  I'm happy to switch technologies
> where it's necessary; here are the things i would be willing to try if
> necessary:
> 
> - Different clustered file storage setup.  What are the possibilities?
> GFS2?  DRBD seems feasible, but it doesn't actually solve anything in
> the above equation, so i'd rather keep the iSCSI NAS.
> 
> - Switching distros?  Possible - my order of preference: Debian squeeze,
> Debian sid, Ubuntu lucid, openSUSE 11.2, CentOS 5.4.
> 
> - Switching cluster stacks?  I've worked with clusters on HP-UX,
> NetWare, OES/Linux 1, heartbeat 1, and heartbeat 2, so i'm sure one more
> change won't kill me, but the more similar in feel it is to pacemaker or
> heartbeat 2, the better.  If using non-integrated OCFS2 cluster
> membership and an older openais or heartbeat version is viable, i'm
> happy to look at that as well, although obviously i'd rather go forward
> than backward.
> 
> - Switching VM technologies?  I guess KVM, VirtualBox, or OpenVZ would
> be viable, but again, it doesn't seem to solve much in the current
> scenario.
> 
> What's the path of least resistance here?
> 
> Thanks in advance,
> Paul

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