[Pacemaker] Build dlm_controld for pacemaker stack (dlm_controld.pcmk)

[Andrew Beekhof]

On Tue, Oct 30, 2012 at 8:42 PM, Bernardo Cabezas Serra
<bcabezas at apsl.net> wrote:
>
> El 2012-10-30 02:14, Andrew Beekhof escribió:
>
>
>> Have you read Section 8.1 and 8.2 of Clusters from Scratch?
>>
> http://www.clusterlabs.org/doc/en-US/Pacemaker/1.1-plugin/html/Clusters_from_Scratch/ch08.html#id985586tl:dr
>>
>> - its very important that all parts of the stack are making decisions
>> based on the same membership and quorum data.
>>
>> There were/are three options to achieve this:
>> 1. everyone talks to pacemaker
>> 2. everyone talks to cman
>> 3. everyone talks to corosync
>>
>> [...]
>>
>>
>> Option 3 is where things are headed, however the only distro that ships
>> it today is Fedora-17 (and shortly 18).
>> In this scenario, all components obtain membership and quorum directly
>> from corosync.
>> So far OCFS2 is the only component that hasn't been updated to support
>> this.
>> This option requires corosync 2.x + pacemaker 1.1.7 or later
>>
>> Does that help?
>
>
> Yes, thanks a lot, now I have things muuuch more clear.
>
> I have a working ocfs2 active/active cluster with option (2), on top of
> ubuntu 12.04:
> https://wiki.ubuntu.com/ClusterStack/Precise
> Works pretty well, but I had some issues with fenced daemon,

Can you elaborate?
1.1.8 is _significantly_ better in terms of its interaction with
dlm/cman initiated fencing.
We (well, mostly David) made some further improvements since then, to
the point were I'm quite confident we've finally nailed it.

> so I wanted to
> try the "head" option, but I misunderstood differences between option (1)
> and (3).
>
> Just for information if someone tries it, ubuntu 12.04 LTS uses cluster-glue
> (1.0.8), openais (1.1.4), corosync (1.4.2), pacemaker (1.1.6) on top of cman
> (3.1.7), and seems also a good distro for option (2).
> I think my option will be to solve current problems and stay on (2) on top
> of ubuntu.
>
>
> However, as it is a new cluster that has to have support for years,

Unless your support window is longer than RHEL6's, you should be pretty safe :-)
But I'm of course happy to help get option 3 working if I can.

> I will
> spend some more time in trying to make option (3), work  building from
> sources on ubuntu (maybe trying FC17, and maybe switching to GFS2. Will
> share if success.
>
> Seems that clusterlabs build guide
> (http://www.clusterlabs.org/wiki/Install#From_Source), does not contemplate
> the dlm part, and that confused me. Will try now with things more clear, and
> comments from Vladislav post about dlm4.
>
>
>
>>> (2) What is the future roadmap about this?> Will future corosync2.0
>>> cluster have dlm issues addressed?
>>
>> The dlm works fine with corosync 2.0 - otherwise GFS2 wouldn't work (I can
>> assure you it does).
>
>
> OK
> Thanks again.
>
> Bernardo.
>
>
>
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