[Pacemaker] [pacemaker][patch 3/4] Simple changes for "Pacemaker Explained", Chapter 6 CH_Constraints.xml

[Tim Serong]

 >>> On 4/11/2011 at 10:23 PM, Andrew Beekhof <andrew at beekhof.net> wrote: 
> On Mon, Apr 11, 2011 at 2:18 PM, Tim Serong <tserong at novell.com> wrote: 
> > On 4/11/2011 at 09:37 PM, Andrew Beekhof <andrew at beekhof.net> wrote: 
> >> On Mon, Apr 11, 2011 at 12:57 PM, Tim Serong <tserong at novell.com> wrote: 
> >> > On 3/21/2011 at 08:20 PM, Andrew Beekhof <andrew at beekhof.net> wrote: 
> >> >> 
> >> >> Small improvement to: 
> >> >> +     The only thing that matters is that in order for any member of a set 
> >> >> to be active, all the members of the previous set must also be active 
> >> >> (and naturally on the same node). When a set has 
> >> >> <literal>sequential="true"</literal>, then in order for any member to 
> >> >> be active, the previous members must also be active. 
> >> >> 
> >> >> +     The only thing that matters is that in order for any member of a set 
> >> >> to be active, all the members of the previous set<footnote><para>as 
> >> >> determined by the display order in the configuration</para></footnote> 
> >> >> must also be active (and naturally on the same node). 
> >> >> + When a set has <literal>sequential="true"</literal>, then in order 
> >> >> for any member to be active, the previous members must also be active. 
> >> > 
> >> > This isn't quite correct. 
> >> > 
> >> > For members within a set (sequential=true), it is true that for a given 
> >> > member to be active, the previous members must also be active. 
> >> > 
> >> > Between sets however, it's the other way around - a given set depends on 
> >> > the subsequent set. 
> >> 
> >> Did I really write it like that? You tested it? 
> > 
> > Yup.  Well, I tested it (pcmk 1.1.5), so I assume you wrote it like that :) 
> > 
> > We want (pardon the ASCII art): 
> > 
> >             /--> C --\ 
> >  G --> F --+---> D ---+--> B --> A 
> >             \- -> E --/ 
> > 
> > Test is: 
> > 
> >  # crm configure colocation c inf: F G ( C D E ) A B 
>  
> Given the well discussed issues with the shell syntax, I'd prefer to 
> see the raw xml actually. 

    <constraints>
      <rsc_colocation id="c" score="INFINITY">
        <resource_set id="c-0">
          <resource_ref id="F"/>
          <resource_ref id="G"/>
        </resource_set>
        <resource_set id="c-1" sequential="false">
          <resource_ref id="C"/>
          <resource_ref id="D"/>
          <resource_ref id="E"/>
        </resource_set>
        <resource_set id="c-2">
          <resource_ref id="A"/>
          <resource_ref id="B"/>
        </resource_set>
      </rsc_colocation>
    </constraints>

> >  # crm resource stop F 
> >     (stops F and G) 
> >  # crm resource start F 
> >  # crm resource stop D 
> >     (stops D, F and G) 
> >  # crm resource start D 
> >  # crm resource stop B 
> >     (stops everything except A) 
> > 
> > That shell colocation constraint maps exactly to the (new) XML shown below 
> > (verified just in case it turned out to be a shell oddity). 
> > 
> >> If so, thats just retarded and needs an overhaul. 
> > 
> > It is a little... confusing. 
> > 
> > Regards, 
> > 
> > Tim 
> > 
> >> > 
> >> > The example colocation chain in Pacemaker Explained right now should thus 
> >> > be changed as follows in order to match the diagram: 
> >> > 
> >> >  <constraints> 
> >> >    <rsc_colocation id="coloc-1" score="INFINITY" > 
> >> >       <resource_set id="collocated-set-1" sequential="true"> 
> >> > -        <resource_ref id="A"/> 
> >> > -        <resource_ref id="B"/> 
> >> > +        <resource_ref id="F"/> 
> >> > +        <resource_ref id="G"/> 
> >> >      </resource_set> 
> >> >      <resource_set id="collocated-set-2" sequential="false"> 
> >> >        <resource_ref id="C"/> 
> >> >        <resource_ref id="D"/> 
> >> >        <resource_ref id="E"/> 
> >> >      </resource_set> 
> >> >      <resource_set id="collocated-set-2" sequential="true" role="Master"> 
> >> > -        <resource_ref id="F"/> 
> >> > -        <resource_ref id="G"/> 
> >> > +        <resource_ref id="A"/> 
> >> > +        <resource_ref id="B"/> 
> >> >      </resource_set> 
> >> >    </rsc_colocation> 
> >> >  </constraints> 
> >> > 
> >> > Regards, 
> >> > 
> >> > Tim 
> >> > 
> >> > 
> >> > -- 
> >> > Tim Serong <tserong at novell.com> 
> >> > Senior Clustering Engineer, OPS Engineering, Novell Inc. 
> >> > 
> >> > 
> >> > 
> >> > 
> >> > _______________________________________________ 
> >> > Pacemaker mailing list: Pacemaker at oss.clusterlabs.org 
> >> > http://oss.clusterlabs.org/mailman/listinfo/pacemaker 
> >> > 
> >> > Project Home: http://www.clusterlabs.org 
> >> > Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf 
> >> > Bugs: 
> >> http://developerbugs.linux-foundation.org/enter_bug.cgi?product=Pacemaker 
> >> > 
> >> 
> > 
> > 
> > 
> > 
> > -- 
> > Tim Serong <tserong at novell.com> 
> > Senior Clustering Engineer, OPS Engineering, Novell Inc. 
> > 
> > 
> > 
> > _______________________________________________ 
> > Pacemaker mailing list: Pacemaker at oss.clusterlabs.org 
> > http://oss.clusterlabs.org/mailman/listinfo/pacemaker 
> > 
> > Project Home: http://www.clusterlabs.org 
> > Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf 
> > Bugs:  
> http://developerbugs.linux-foundation.org/enter_bug.cgi?product=Pacemaker 
> > 
>  




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