[Pacemaker] clusters on virtualised platforms

[Digimer]

To add my voice to this; This is exactly what I do as well (though on 
RHEL + RHCS/High-Availabiltiy Add-On):

https://alteeve.ca/w/AN!Cluster_Tutorial_2

As Lars said, it's a very portable solution as it will make any OS HA 
without the user of the OS or any software in it being aware of the HA 
components.

digimer

On 17/07/14 11:36 PM, Nick Cameo wrote:
> "Instead, have the HA hypervisor layer protect the VM as a clustered
> service"
>
> I had to read this a couple of times Lars, and it's interesting. If I
> understand correctly
> run the cluster on bare metal, taking care of the virtual machine
> instances on the same
> box?
>
> Kind Regards,
>
> Nick
>
>
>
> On Thu, Jul 17, 2014 at 5:48 AM, Lars Marowsky-Bree <lmb at suse.com
> <mailto:lmb at suse.com>> wrote:
>
>     On 2014-07-17T03:48:51, Alex Samad - Yieldbroker
>     <Alex.Samad at yieldbroker.com <mailto:Alex.Samad at yieldbroker.com>> wrote:
>
>      > I wonder if there Best practise or how to, on how to run clusters
>     on say VMWare.
>
>     We've got many customers running SLE HA (pacemaker/corosync) cluster
>     inside virtual machines. That works fine.
>
>     There are a few obvious caveats. Make sure the VMs are actually running
>     on different nodes being the most obvious one.
>
>     Fencing is another. Typically these environments have shared storage, or
>     can easily get it via iSCSI (and even easily get 3 devices), so we
>     recommend the use of "sbd" for fencing.
>
>     That - sort of - also implies a network-based quorum that is richer than
>     merely being able to ping a node.
>
>     There are some other concerns that are harder to address. We've seen VMs
>     "freeze" when the hypervisor deems to take a snapshot or during live
>     migration. You don't want that to affect the cluster; so set the
>     corosync token timeout to an appropriate value.
>
>
>     In general, if you can, it makes more sense to run HA closer to the
>     hardware and not inside the VM - instead, have the HA hypervisor layer
>     protect the VM as a clustered service. That has many advantages from an
>     architectural and reliability perspective, not the least of which is
>     that then HA becomes available for *all* VMs if needed, and the folks
>     managing their virtualized service don't have to worry about HA
>     themselves.
>
>     Unfortunately, a few customers have choosen hypervisors whose idea of
>     "HA" and "IO isolation" makes me weep, so they're stuck with running HA
>     inside their VMs. I consider this a blatant failure of the HVM.
>
>
>     Regards,
>          Lars
>
>     --
>     Architect Storage/HA
>     SUSE LINUX Products GmbH, GF: Jeff Hawn, Jennifer Guild, Felix
>     Imendörffer, HRB 21284 (AG Nürnberg)
>     "Experience is the name everyone gives to their mistakes." -- Oscar
>     Wilde
>
>
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>
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Digimer
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