[libvirt] (no subject)

[Guido Günther <agx sigxcpu org>]

On Wed, Oct 15, 2008 at 09:59:12PM +0100, Daniel P. Berrange wrote:
> When you get to that level of cleverness, it seems to me that it is verging 
> on a complete re-implementation of DLM (distributed lock manager), which 
> really, AFAIK, needs a proper cluster setup so it can safely fence 
> mis-behaving nodes, and avoid quorum/split-brain problems.
I've been toying with the idea of using DLM for libvirt earlier this
year [1](but infered from other postings on the list that this would be out
of scope for libvirt - probably should have asked). I looked at vm based
locks then but having storage based locks is even better.

Currently you have to make sure "manually" that people using i.e.
virt-manager[2] don't accidentally fire up VMs managed via e.g.
rgmanager.

Having cluster wide storage based locks would be an awesome solution.
 -- Guido


[1] using the rather simple lock_resource() and unlock_resource() API:
  http://git.fedorahosted.org/git/cluster.git?p=cluster.git;a=blob;f=dlm/doc/libdlm.txt
[2] i.e. by having virt-manager hooked to all libvirtds in the cluster
and allowing to start each uuid only once