[Pacemaker] Does pingd works on openais?

Atanas Dyulgerov atanas.dyulgerov at postpath.com
Fri Mar 7 13:11:46 EST 2008

-----Original Message-----
From: Lars Marowsky-Bree [mailto:lmb at suse.de] 
Sent: Thursday, March 06, 2008 11:08 AM
To: The Pacemaker cluster resource manager
Subject: Re: [Pacemaker] Does pingd works on openais?

On 2008-03-06T20:55:50, Atanas Dyulgerov <atanas.dyulgerov at postpath.com> wrote:

>> Isn't Red Hat Cluster Suite using CMAN on top of openais? Correct me is >I'm wrong. They claim it is suitable for production use.
>I don't think CMAN is running on top of openAIS in the shipping distros
>just yet.

Hm, I left with the impression openais is part of the red hat cluster suite in some way: http://sources.redhat.com/cluster/faq.html#what

>Even with openAIS being production ready on its own, that doesn't
>mean the CRM port will have all glitches ironed out yet. We love early
>innovators, just be sure what you're getting ;-)
>> >Hm? openAIS already supports locking.
>> Yes, I know openais supports locking. That's why Pacemaker must
>> support those locking features to lock its resources. Currently
>> Pacemaker cannot lock resources (iscsi, network block devices,
>> filesystems like GFS, OCFS2 and etc.), right?
>That's something the resource agents would need to do. And as far as I
>know, openAIS does not do the resource level locking you refer to; but
>Pacemaker internally ensures exclusive access to them.

Yes, Pacemaker should support resource locking.

>Hm? Heartbeat has support for OCFS2, which also supports locking in more
>recent versions. But "resource locking" seems to be something else. That
>heartbeat does not need a quorum disk is actually a _feature_, you know.

This is a new info for me. I knew that ocfs2 includes a simple node information layer which holds a description of the systems which make up the cluster. OCFS2 also includes a simple heartbeat implementation for monitoring which nodes are actually alive - tcp-based messaging system which is used to talk between nodes in a cluster.

So you are saying that Heartbeat replaces successfully all of the above? Can OCFS2 get its membership information from Heartbeat? Does Heartbeat CRM controls OCFS2 distributed lock manager?

If true, could you send me some links for that? Patches, docs, sample configuration in Heartbeat? Thanks!

>The first version of GFS to work with openAIS will likely be GFS2, not
>yet shipping either.
>> What will be the answer of Heartbeat/Pacemaker/OpenAIS? What would say >about iSCSI+OCFS2+OpenAIS+Pacemaker solution although 
>That is going to work just fine, though if you're using GFS2 or OCFS2 on
>top of GNBD or iSCSI (because you don't have a SAN, presumably), I'd
>really wonder why you're not directly using NFS?

Hm? GFS and GNBD works with red hat cluster suite only?

I don't have SAN. I'm looking for a cheaper solution. The reason I'm not using NFS is the slower performance compared to the fastest GNBD and iSCSI. Also a very specific service application is running on the cluster and it does not get along with NFS very well.

>> 	- iscsi software targets does not support locking ("persistent >reservation" was the word I think)
>Why would it need to support that?

To lock the network block device if node fails to bring down the service application or if for any reason the cluster software fails on that node. In that case the application will be started on a passive node and the cluster might end up with two nodes which try to access the same data.

GNBD supports locking but unfortunately it operates with red hat cluster suite only. 

>> 	- OCFS2 is not completely stable and it is driven by its own cluster 
>OCFS2 is not completely stable?
That's what I read on various forums... not my personal experience.

>On SLES10, we ship OCFS2 with integration into the heartbeat/CRM


Teamlead Kernel, SuSE Labs, Research and Development
SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg)
"Experience is the name everyone gives to their mistakes." -- Oscar Wilde

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