[Pacemaker] Enable remote monitoring

[Andrew Beekhof]

On 06/12/2012, at 10:42 PM, Lars Marowsky-Bree <lmb at suse.com> wrote:

> On 2012-12-06T22:25:40, Andrew Beekhof <andrew at beekhof.net> wrote:
> 
>> But any failures of the nagios agents would count against the VM's
>> migration-threshold.
>> So if moving were the right thing to do, it would have done it already.
> 
> OK. I think this was due to me still being stuck on the workings of an
> order constraint, but of course if the failures are instead attributed
> to the container, this would happen automatically already. True.
> 
> (Incidentally, I like "attribute", "ascribe" better than "delegate"
> because to me, they better fit what's going on, if we sticked with
> "delegate-failures". Just saying. ;-)

My use of "delegate" comes from my time with ObjectiveC where its common practice to use them for "I'm not going to handle X but here is something that does" style functionality.
Which fits nicely with what we're doing here.

container="vm"  also works though.

> 
>>> We already have on-fail settings. How would these play together?
>> Good question. My initial thought was that it would be up to on-fail
>> settings in the VM.
> 
> I'd prefer to keep that separate (as proposed below). Because if an
> action of the *VM* really fails, I may want an admin to look into it
> (why could the bloody hypervisor not start/stop it?), which is different
> from restarting the VM if one of the resources within it needs that.
> 
>>> Would it even make sense to have on-fail="restart-container"? (Or a
>>> nicer wording.)
>>> 
>>> Hmmm. That might work. We allow a "container" to be specified as a meta
>>> attribute.
>>> 
>>> If set, on-fail would default to restart container for most actions. But
>>> admins could actually modify it - say, they might want to set
>>> monitor on-fail="ignore" to just get notified. And when we move forward
>>> to whiteboxes, we could have start/monitor/promote/demote
>>> on-fail="restart" (like now) and stop on-fail="restart-container".
>>> 
>>> That appears reasonably neat?
>> It does actually.
>> I wasn't originally thinking it was necessary but it makes sense now
>> that you point it out.
> 
> Yes, I think I like this too now.
> 
> Uhm. Would "container" imply ordering + colocation, or would we still
> need them grouped (resource_set'ed, whatever)?

Ordering: absolutely
Colocation is less clear, I think the default is no but David has suggested an additional meta attribute to turn it on.

> 
> My, design is hard. ;-)

I like where we got to in the end though, it should handle both white and black box monitoring nicely.
Being a PITA can have its benefits.