[Pacemaker] Manging Virtual Machine's resource

[Nitin]

On Wed, 2008-05-21 at 11:13 +0800, Xinwei Hu wrote:
> We had a deployment of this kind running for more then a half year.
> 2 lessons we had so far:
> 
> 1. Start a "standalone" heartbeat inside VM is the best option so far.
>    i.e "ucast lo 127.0.0.1" in ha.cf
>    It's the simplest way to have monitoring and restarting inside VM.

Yes. we thought of that but want to use it as the last resort.

> 2. Manage VMs as Xen resources in a cluster of all dom0.
>    However,
>    a. VMs might be migrated between dom0s anytime, so set dom0 as a
> parameter to STONITH plugin is not ideal in practice. (The same
> problem applies to VMware ESX server also.)
>    b. VM is a typical example that we'd better support "inheritance"
> for RA. VM's RA can only tell whether it's running, but there're
> different ways to tell if the OS (Linux, BSD, Windows, Netware) inside
> is health.

If this "inheritance" implementation can bring proportionate value then
let us implement it. Lon Hohberger has already shown interest in this. 

May I request to Andrew Beekhof and other veterans :) to advise on
implementation complexity versus use of this feature.

Thanks for sharing your valuable experience.
> 
> My .2c
> 
> 2008/5/19 Andrew Beekhof <beekhof at gmail.com>:
> >
> > On May 19, 2008, at 7:14 AM, Nitin wrote:
> >
> >> On Fri, 2008-05-16 at 15:08 +0200, Andrew Beekhof wrote:
> >>>
> >>> On May 16, 2008, at 3:04 PM, Nitin wrote:
> >>>
> >>>> Hello,
> >>>>
> >>>> I would like to make my virtual machines (DomUs) resources to
> >>>> participate in the HA cluster. Dom0 (Physical Host) may or may not
> >>>> have
> >>>> resources.
> >>>>
> >>>> To do this I would like to treat DomUs as *resource* in the cluster as
> >>>> opposed to treating them as *nodes*. I am planning to write OCF
> >>>> resource
> >>>> agents for virtual machines. But I am not very sure about how to
> >>>> make a
> >>>> resource's resource to participate in the cluster.
> >>>>
> >>>> Is there any configuration in existing structure to achieve this??
> >>>> If no
> >>>> then please tell me how to go about creating a "container" resource in
> >>>> CRM.
> >>>
> >>> Why not just use the Xen agent if you don't want them to be cluster
> >>> nodes?
> >>> Or do you mean that you want them to both be resources and to run
> >>> other resources too?
> >>
> >> Yes. Please advise me how to go about it.
> >> Thanks a lot for reply.
> >
> > We don't have a clean way to do that yet
> >
> > Possible options:
> > a) start the services at VM boot (you don't get monitoring)
> > b) start the services at VM boot and modify the Xen agent to monitor the
> > services inside the VM (ugly)
> > c) add a proxy resource to start/stop/monitor the services inside the VM
> > (complex)
> > d) implement a generic version of c)
> > e) have the VM join the cluster (makes stonith and quorum "interesting")
> > f) wait for us to implement clusters-of-clusters which also solves this
> > scenario "for free"
> > g) something else i've not thought of
> >
> 
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