CentOS virt - Jun 2012 - Fencing question(s)

I've got a Centos 5.8 box that I use for testing Xen VMs. I'm trying to 
setup some Centos 6.2 hosts in a high availability situation. I've tried 
the pacemaker route and couldn't get the connection established, so 
thought I'd try the RH-preferred methods. Mind you, all of these VMs are 
on the same host.

Using Conga, it seems that I need some sort of fencing device, which 
doesn't really work in a VM environment. I'm guessing it's the same
with
command line configuration.

Firstly, is it really possible to set up two VMs on the same machine to 
do HA? I can't see why not, but I'm not the best source of knowledge on 
any of this.

Secondly, is there a useable fencing device that would work in a virtual 
environment for me to test with? I'd really like to avoid fencing 
altogether, even once in production, but every thing I read suggests 
against that.

Any type of reply would be appreciated.

steve campbell

On 06/21/2012 01:01 PM, Steve Campbell wrote:
> I've got a Centos 5.8 box that I use for testing Xen VMs. I'm
trying to
> setup some Centos 6.2 hosts in a high availability situation. I've
tried
> the pacemaker route and couldn't get the connection established, so
> thought I'd try the RH-preferred methods. Mind you, all of these VMs
are
> on the same host.
>
> Using Conga, it seems that I need some sort of fencing device, which
> doesn't really work in a VM environment. I'm guessing it's the
same with
> command line configuration.
>
> Firstly, is it really possible to set up two VMs on the same machine to
> do HA? I can't see why not, but I'm not the best source of
knowledge on
> any of this.
>
> Secondly, is there a useable fencing device that would work in a virtual
> environment for me to test with? I'd really like to avoid fencing
> altogether, even once in production, but every thing I read suggests
> against that.
>
> Any type of reply would be appreciated.
>
> steve campbell
"HA" on the same node is kind of contradictory. However, yes, you can 
build (and fence) a cluster of VMs on the same host. Look at fence_xvm 
or fence_virsh.

Can you use two servers? If so, you can build a truly HA cluster for 
your VMs;

https://alteeve.com/w/2-Node_Red_Hat_KVM_Cluster_Tutorial

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