On Fri, Apr 18, 2008 at 04:39:18PM -0500, Mike McGrath wrote:
On Fri, 18 Apr 2008, Kostas Georgiou wrote:
> On Fri, Apr 18, 2008 at 03:33:22PM -0500, Mike McGrath wrote:
>
> > The only reason we haven't done this already is the inability to detect if
> > the box is already up somewhere (which is something we need already)
> > Consider this scenario:
> >
> > app1 running on xen1 (which is having high load from koji1 also on xen1)
> >
> > People complain about the wiki.
> >
> > We move app1 to a more free box, xen7.
> >
> > high load causes CRASH
> >
> > xen1 reboots. Attempts to bring app1 up (already up on xen7)
> >
> > Two machines try to write to the same disk - DOOM.
>
> What about using gfs (or maybe just nfs from the netapp) to keep the
> contents of /etc/xen/auto "synced" between hosts? Having /etc/xen/auto
> as a link to [sharedarea]/auto-xenXX and making sure that the entries
> there are unique will be a good start for a solution I think.
>
Network file shares are ill suited for tasks like configuration management
IMHO.
I don't disagree, I don't like it either.
RedHat magazine had an article[1] recently about xen failover using
conga. It might give some ideas even if you prefer not to use gfs
(probably a bad idea to have host images in gfs anyway).
Kostas
[1]
http://www.redhatmagazine.com/2007/08/23/automated-failover-and-recovery-...