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

Tue Oct 30 06:33:56 UTC 2012

29.10.2012 22:10, David Vossel wrote:
> 
> 
> ----- Original Message -----
>> From: "Bernardo Cabezas Serra" <bcabezas at apsl.net>
>> To: pacemaker at oss.clusterlabs.org
>> Sent: Monday, October 29, 2012 11:51:51 AM
>> Subject: [Pacemaker] Build dlm_controld for pacemaker stack	(dlm_controld.pcmk)
>>
>>
>> Hello,
>>
>> disclaimer: I have posted this issue to linux-ha list too a couple of
>> days ago. I'm sorry if this is not the correct list, and thanks if
>> you can give me a hint about which cluster stack should I use for
>> ocfs2 by now.
>>
>> I'm trying to compile all stack for corosync + pacemaker + dlm +
>> ocfs2 (with dlm_controld.pmk), without cman stack. I'm following the
>> "From source" Pacemaker guide.
>>
>> After some days trying to compile the correct combination of
>> sources/versions, I have no success, and I'm not sure if at this
>> moment this is possible.
>>
>> The fist problem was that cluster removed support for dlm_controld
>> with pacemaker stack. Last version with support was 3.0.17.
>> But this was done some years ago, and as far as I have been able to
>> understand, things are still broken.
>>
>>
>> The most relevant info found about this issue are these threads from
>> Andrew Beekhof and Vladislav Bogdanov, wich suggest to compile
>> dlm_controld from Cluster, applying some patches. They report it
>> worked (whith some remaining issues):
>>
>> http://oss.clusterlabs.org/pipermail/pacemaker/2009-October/003064.html
>> http://www.mail-archive.com/pacemaker@oss.clusterlabs.org/msg09959.html
>>
>> But most recent issue about this is a year ago, and seems that things
>> are still broken.
>> I haven't been able to compile, with lots of errors, so I'm currently
>> asking if this is the right way, becouse seems that nobody else is
>> willing to use this...
>>
>>
>> At cluster page, they state that now DLM code has been separated from
>> cluster:
>> https://fedorahosted.org/cluster/wiki/HomePage
>>
>> But this dlm project (that seems to have pcmk support), depends on
>> corosync 2.0, so it can't run with last pacemaker (1.1.8). (can it?)
>> http://git.fedorahosted.org/git/dlm.git
>>
>> Before spending more time with this, I wanted to ask for the right
>> way to do things.
>> So Questions are:
>>
>> (1) Is it by now possible to get an ocfs2 corosync + pacemaker
>> cluster, without cman, and dlm_controld with pcmk stack? (if yes
>> which repos/versions)?
> 
> I don't know about ocfs2, but using the dlm without cman is
> definitely possible right now. It should work. I tried it out a few months ago. We
> even have a tutorial outlining how to do gfs2 + dlm + pacemaker 1.1.8 + corosync 2.0.
> http://www.clusterlabs.org/doc/en-US/Pacemaker/1.1/html/Clusters_from_Scratch/
> Take a look at the active/active section.

One remark about that - it requires that gfs2 communicates with dlm in
the kernel space - so gfs_controld is not longer required. I think
Fedora 17 is the first version with that feature. And it is definitely
not available for EL6 (centos6 which I use).

But I have preliminary success running GFS2 with corosync2 and pacemaker
1.1.8 on EL6. dlm4 runs just fine as is (although it misses some
featured on EL6 because of kernel). And it still includes (not
documented) option enable_fscontrol, so user-space communication with fs
control daemons is supported. Even it that feature will be removed
upstream, it can be easily returned back - just several lines of code.
And I ported gfs_controld from cman to corosync2 (patch is very dirty
yet, made with scissors and needle, just a proof-of-concept that it even
can work). Some features are unsupported (f.e. nodir) and will not be
implemented by me.

I can send that patch here for those who interested. I think the same
method may apply to ocfs2 (I'm allergic to it so I wont even look).

Vladislav

> 
> Hope that helps.
> 
> -- Vossel
> 
>> (2) What is the future roadmap about this? Will future corosync2.0
>> cluster have dlm issues addressed?
>>
>> Also, I have read (also Andrew post) that OCFS2 cluster could have
>> problems on top of corosync 2.0, as OCFS2 has't ben ported (GFS2 was
>> ported).
>> http://www.gossamer-threads.com/lists/linuxha/pacemaker/78538
>> so:
>> (3) Is GSF2 a better future option in terms of support, for linux-ha
>> clusters?
>>
>>
>> More details about pcmk dlm_controld:
>> I found that Suse have always been mantaining cman-free cluster
>> stack, so I have tried to find dlm in its packages.
>> Found:
>> http://rpmfind.net//linux/RPM/opensuse/factory/x86_64/libdlm-3.00.01-24.5.x86_64.html
>>
>> But also I have had lots of compilation problems, trying several
>> pacemaker, versions, also the suse-patched ones. Haven't been able
>> to successfully complie a dlm_controld.
>>
>>
>> Thanks and Regards,
>> Bernardo
>> --
>> APSL
>> 	APSL
>> 	Bernardo Cabezas Serra
>> Responsable Sistemas
>> 	Ada Byron, edificio NTIC 2ºA
>> 07121 ParcBit
>> 	Mail: bcabezas at apsl.net
>> Skype: bernat.cabezas
>> Tel: 971439771
>>
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>>
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