[CentOS] does anyone have experience with clusters?

Wed Dec 3 11:16:54 UTC 2008
Rudi Ahlers <rudiahlers at gmail.com>

On Wed, Dec 3, 2008 at 11:52 AM, Fabian Arrotin
<fabian.arrotin at arrfab.net> wrote:
> Rudi Ahlers wrote:
>> Hi all,
>> I want to start experimenting with clusters, and I would like to use
>> normal desktop grade hardware for this. I have some extra PC
>> components lying around, enough to build 3 - 4 moderate desktops with
>> a PIV / C2D CPU & 512MB - 1GB RAM each. All the machines should have
>> at least a 100MB NIC, but I can add a gigabit NIC to the machines that
>> doesn't have it if need be.
>> I have used Linux Heartbeat to failover a MySQL cluster before, and
>> it's actually been running very well for about 3 years now. But, I
>> want to start looking @ total clustering, with DRBD - where everything
>> (not just MySQL) is being replicated across the 4 machines. I'm also
>> intereated in load balancing.
>> Has anyone done anything like this?
>> The cluster will be running / hosting a few XEN Virtual Machines, and
>> idealy if one PC / server dies (hardware failure / power failure /
>> etc), then on of the other machines should still be running the
>> virtual machines, i.e. no downtime. Is this possible? Can somone steer
>> me into a direction where I can get more info on this?
>> My aim: to use common, cheap PC equipment & CentOS for the project, I
>> don't want to spend any more money, and want to use what I have.
> So if i understand you correctly, the goal is to have a Xen farm running
> on multiple hosts ?
> You can use the included clustering solution (conga) to do that but
> normally it needs a shared storage to store the domU's ..
> What i've already tested is to use drbd with GFS2 so that all the local
> storage act like only one for all the nodes but that specific drbd part
> is not covered by conga. But i don't get the point about load-balancing
> ? you were talking about xen domU's and previously about mysql ... i
> suppose mysql will be running inside of a domU ?
> BTW the RHCS (conga) doesn't provide by itself a load-balancing solution
> You can read the following article that was really interesting when i
> wanted to test that (except that it doesn't deal with drbd, but you can
> find informations on the wiki for that) :
> http://www.redhatmagazine.com/2007/08/23/automated-failover-and-recovery-of-virtualized-guests-in-advanced-platform
> --
> -
> Fabian Arrotin <fabian.arrotin at arrfab.net>
> "Internet network currently down, TCP/IP packets delivered now by
> UPS/Fedex ..."
> _______________________________________________

Yes, the idea is to run a XEN farm. Each VPS will have it own set of
sofware running, from Windows to Linux, with SQL / Web / Email / etc.

With regards to load balancing, I need it so that the total load of
all the XEN VPS's can be spread out among the XEN servers, almost like
a super computer. How will I do this?

Kind Regards
Rudi Ahlers