[Pacemaker] Enable remote monitoring

[Andrew Beekhof]

On Fri, Nov 9, 2012 at 10:13 AM, Andrew Beekhof <andrew at beekhof.net> wrote:
> On Thu, Nov 8, 2012 at 7:18 PM, Lars Marowsky-Bree <lmb at suse.com> wrote:
>> On 2012-11-08T14:24:40, "Gao,Yan" <ygao at suse.com> wrote:
>>
>>> > What do you propose the XML should look like?
>>> Should be like:
>>> ...
>>> <op id="vm-monitor-30" name="monitor" class="nagios" type="ftp"
>>> interval="30s" ignore-first-failures="true">
>>
>> If we make "ignore-first-failures" a time period, we can also limit the
>> time the cluster ignores this.
>>
>> Downside, that I have just realized - resources which depend on this
>> one, and might want to depend on a service the container provides.
>>
>> (This could be an argument to go back to the "configure them as
>> primitives that are managed-by-proxy via the container resource", sigh.)
>
> Yeah, that is a reasonably big downside.
> /me predicts a whole lot of start_delays being added which would be
> kinda fragile :)
>

So I was just explaining the problem and context to David... his
comment was "aren't these just unmanaged resources and some
constraints?".

Of course its slightly more complex than that, but what if we made a
"container" type in the PE?
Something analogous to groups (ie. a parent with N children) but
possibly without the internal ordering.

That would give you ordering capabilities "for free" and we could
easily make it an option to start/stop the children later on too, if
people wanted that.
Conceptually its also a little closer to how the admin probably thinks
of the system and we'd make the semantics be that you don't start
monitoring the children until the parent is fully up and any failures
are a failure of the parent (optional?).
For GUIs and shells there is also no need to munge the parent and
child metadata.

David has volunteered for the PE bits if no-one there wants it.  What
do you think?

Pseudo example:

<container id=myguest class=ocf provider=heartbeat type=VirtualDomain>
   ...parent and shared parameters/options here...

  <primitive id=ftp-server class=nagios type=ftp>
     ...ftp specific parameters/options here if any...
  </primitive>

  <primitive id=http-server class=nagios type=apache>
     ...apache specific parameters/options here if any...
  </primitive>

</container>