[Pacemaker] Convenience Groups - WAS Re: [Linux-HA] Unordered groups (was Re: Is 'resource_set' still experimental?)

[David Vossel]

----- Original Message -----
> From: "Alan Robertson" <alanr at unix.sh>
> To: pacemaker at oss.clusterlabs.org, "Andrew Beekhof" <andrew at beekhof.net>
> Cc: "Dejan Muhamedagic" <dejan at hello-penguin.com>
> Sent: Thursday, April 19, 2012 10:22:48 AM
> Subject: [Pacemaker] Convenience Groups - WAS Re: [Linux-HA] Unordered groups (was Re: Is 'resource_set' still
> experimental?)
> 
> Hi Andrew,
> 
> I'm currently working on a fairly large cluster with lots of
> resources
> related to attached hardware.  There are 59 of these things and 24 of
> those things and so on and each of them has its own resource to deal
> with the the "things".  They are not clones, and can't easily be made
> clones.
> 
> I would like to be able to easily say "shut down all the resources
> that
> manage this kind of thing".    The solution that occurs to me most
> obviously is one you would likely call a "double abomination" ;-) -
> an
> unordered and un-colocated group.  It seems a safe assumption that
> this
> would not be a good path to pursue given your statements from last
> year...
> 
> What would you suggest instead?
> 

This might be a terrible idea, but this is the first thing that came to mind.

What if you made a Dummy resource as a sort of control switch for starting/stopping each "group" of resources that control a "thing".  The resource groups wouldn't actually be defined as resource groups, but instead would be defined by order constraints that force a set of resources to start or stop when the Dummy control resource starts/stops.

So, something like this...

Dummy resource D1
thing resource T1
thing resource T2

- If you start D1 then T1 and T2 can start.
- If you stop D1, then T1 and T2 have to stop.
- If you flip D1 back on, then T1 and T2 start again.
order set start (D1) then start (T1 and T2)


-- Vossel