[Pacemaker] RFC: cluster-wide attributes

[Tim Serong]

On 6/30/2010 at 09:42 PM, Andrew Beekhof <andrew at beekhof.net> wrote: 
> On Thu, Jun 24, 2010 at 5:41 PM, Lars Marowsky-Bree <lmb at novell.com> wrote: 
> > Hi, 
> > 
> > another idea that goes along with the previous post are cluster-wide 
> > attributes. Similar to per-node attributes, but basically a special 
> > section in <configuration>: 
> > 
> >        <optional> 
> >        <element name="cluster_attributes"> 
> >          <zeroOrMore> 
> >            <element name="attributes"> 
> >              <externalRef href="nvset.rng"/> 
> >            </element> 
> >          </zeroOrMore> 
> >        </element> 
> >        </optional> 
>  
> Do we need a new section? Or can they go in with cluster-infrastructure etc? 
>  
> > These then would also be referencable in the various dependencies like 
> > node attributes, just globally. 
> > 
> > Question - 
> > 
> > 1. Do we want to treat them like true node attributes, i.e., per-node 
> > attributes would override the cluster-wide settings - or as indeed a 
> > completely separate class? I lean towards the latter, but would solicit 
> > some more opinions. 
>  
> Not sure it really gives you anything by making them a separate class. does  
> it? 
> Just means you have to look twice right? 

Just for the record, a use case of this came up on IRC last week:
you could specify cluster-wide standby="on", so new nodes joining the
cluster would automatically join in standby mode, with the admin
activating them later (per-node standby="off" thus overriding cluster-
wide attribute).

Regards,

Tim


-- 
Tim Serong <tserong at novell.com>
Senior Clustering Engineer, OPS Engineering, Novell Inc.