[Pacemaker] The main road of the cluster stack evolution

[Lars Marowsky-Bree]

On 2013-06-10T19:26:20, Халезов Иван <i.khalezov at rts.ru> wrote:

> 1) The RedHat company is planning to drop corosync support and wants to
> switch to CMAN. (
> http://www.gossamer-threads.com/lists/linuxha/pacemaker/84662 )

To the best of my understanding, this is not correct. Red Hat will
continue to support corosync, and instead it is the cman support that
has a bad life expectancy. (But take this with a grain of salt, as I'm
obviously not privvy to RHT insights ;-)

SUSE will continue to support Pacemaker on top of corosync, as we've
done in SLE HA 11. Our future roadmap will stay with that, so we get to
skip the intermediate effort of cman. Of course, there'll be a major
update in the next major SUSE Linux Enterprise version to base on latest
upstream (corosync 2.x, etc).

> 2) What is the best tool for cluster management: crm, pcs or something else?
> 
> Redhat switches to pcs and drops crm, but SUSE prefers crmsh tool.
> 
> Why? What tool will you advice to use?

This is bound to be one of those emacs versus vi issues. People have
different preferences.

crm shell is currently certainly more mature and does more (including a
history explorer, integration with the policy engine's test mode, or the
mere ability to show the configuration in a non-xml syntax), and better
tested.

SUSE has no interest in abandoning it; and that crm shell is focused
only on managing pacemaker is a bit of a red herring, since there's
nothing that prevents crm shell from growing in that direction. We'll
continue to support crm shell, and will make sure it continues to work
with latest upstream releases.

It remains to be seen if there's common ground that allows some code
sharing between crm shell and pcs. One hopes.

(From an ISV/user/contributor/doc author preference, this must be the
most painful split ever, because it means all documentation has to be
written twice. Sigh. It's so very hard not to rant!)

But in summary, both are viable options.

> 3) What version of pacemaker should I prefer for using on RedHat 6.3 (or
> 6.4) ?
> 
> The version from the vendor (Pacemaker 1.1.7 for RedHat 6.3 and Pacemaker
> 1.1.8 for RedHat 6.4) or the upstream version from Github?
> 
> I usually prefer software versions coming from the distribution, because I
> hope they are well-tested and supported by the vendor.
> But, as I know, Pacemaker is a teсhnology preview in RedHat 6, so they don't
> response for it stability.
> Also, all the same, I have to rebuild Redhat src.rpm package ( for adding
> corosync 2.3 support into pacemaker)

Recompiling major components such as corosync/pacemaker from source will
make your cluster stack unsupported by the vendor - on either RHEL or
SLE HA. So you might as well go with the latest upstream versions on the
basis that that has the most fixes, and is the version you can get
community support for.


Regards,
    Lars

-- 
Architect Storage/HA
SUSE LINUX Products GmbH, GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer, HRB 21284 (AG Nürnberg)
"Experience is the name everyone gives to their mistakes." -- Oscar Wilde