[Pacemaker] Enable remote monitoring

[Lars Marowsky-Bree]

On 2012-11-08T16:15:50, Andrew Beekhof <andrew at beekhof.net> wrote:

> > And no, I'm not proposing that we allow overriding the
> > class/provider/type tuple for start/stop ;-)
> Did you consider having the VirtualDomain do the nagios redirect for
> monitor operations?
> If so, what was the drawback?

The Xen agent has a call-out. Sucks to configure, because there is no
GUI magic (i.e., with the metadata for configuring that etc). And, yes,
that'd work, and look pretty much the same thing - except that
"nagios:httpd" (for example) would read "params callout=nagios:httpd".

The downside is the configuration syntax and that each RA that an admin
wants to call a different monitor for needs to support it, and the UI
needs to be independently taught about it as well, etc.


> > Third, since the "start" of the base container may return before the
> > guest is fully booted (to stick with the VM resource), we may need an
> > additional timeout here. We *could* abuse start-delay (which might
> > finally give it some legitimate use), but looping until we got the first
> > success also appears attractive.
> My concern there is that there needs to be a finite termination point
> for the "its still bad" looping.
> No better ideas yet though.

The monitor will only ever start after the base is at least started, so
we can loop for, say, thrice the timeout or something.

> > The one downside here is that, unless we modify the PE or make the
> > update to the CIB special somehow, the tools can't show that those
> > ops/services aren't yet reporting healthy. But I think this trade-off is
> > acceptable. And might be useful in other scenarios too.
> You do or dont want to show them as unhealthy?  I'm not parsing this well.

I'd like to show that, but it isn't so easy in this approach for the
initial monitor.


Regards,
    Lars

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Architect Storage/HA
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