[Linux-cluster] Cluster node without access to all resources -trouble

[Janne Peltonen]

On Thu, Jun 28, 2007 at 11:50:07AM -0400, Robert Gil wrote:
> What version of cluster are you running?

[jmmpelto at pcn3 ~]$ sudo rpm -qa 'lvm*cluster|cman|rgmanager'
cman-2.0.60-1.el5
lvm2-cluster-2.02.16-3.el5
rgmanager-2.0.23-1.el5.centos

I'm not running rgmanager-2.0.24 because it didn't seem to run the
script status checks (!).


--Janne

> -----Original Message-----
> From: linux-cluster-bounces at redhat.com
> [mailto:linux-cluster-bounces at redhat.com] On Behalf Of Janne Peltonen
> Sent: Thursday, June 28, 2007 11:46 AM
> To: linux-cluster at redhat.com
> Subject: [Linux-cluster] Cluster node without access to all resources
> -trouble
> 
> Hi.
> 
> I'm running a five node cluster. Four of the nodes run services that
> need access to a SAN, but the fifth doesn't. (The fifth node belongs to
> the cluster to avoid a cluster with an even number of nodes.
> Additionally, the fifth node is a stand-alone rack server, while the
> four other nodes are blade server, two of the in two different blade
> racks - this way, even if either of the blade racks goes down, I won't
> lose the cluster.) This seems to create all sorts of trouble. For
> example, if I try to manipulate clvm'd filesystems on the other four
> nodes, they refuse to commit changes if the fifth node is up. And even
> if I've restricted the SAN-access-needing services to run only on the
> four nodes that have the access, the cluster system tries to shut the
> services down in the fifth node also (when quorum is lost, for example)
> - and complains about being unable to stop them and, on the nodes that
> should run the services, refuses to restart them until I've removed the
> fifth node from the cluster and fenced it. (Or, rather, I've removed the
> fifth node from the cluster and one of the other nodes has successfully
> fenced it.)
> 
> So.
> 
> Is it really necessary that all the members in a cluster have access to
> all the resources that any of the members have, even if the services in
> the cluster are partitioned to run in only a part of the cluster? Or is
> there a way to tell the cluster that it shouldn't care about the fifth
> members opinion about certain services; that is, it doesn't need to
> check if the services are running on it, because they never do. Or
> should I just make sure that the fifth member always comes up last (that
> is, won't be running while the others are coming up)? Or should I aceept
> that I'm going to create more harm than avoiding by letting the fifth
> node belong to the cluster, and just run it outside the cluster?
> 
> Sorry if this was incoherent. I'm a bit tired; this system should be in
> production in two weeks, and unexpected problems (that didn't come up
> during testing) keep coming up... Any suggestions would be greatly
> appreciated.
> 
> 
> --Janne
> --
> Janne Peltonen <janne.peltonen at helsinki.fi>
> 
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-- 
Janne Peltonen <janne.peltonen at helsinki.fi>