"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 <l...@suse.com> wrote: > On 2014-07-17T03:48:51, Alex Samad - Yieldbroker < > alex.sa...@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 > > > _______________________________________________ > Pacemaker mailing list: Pacemaker@oss.clusterlabs.org > http://oss.clusterlabs.org/mailman/listinfo/pacemaker > > Project Home: http://www.clusterlabs.org > Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf > Bugs: http://bugs.clusterlabs.org >
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