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

[Robert Gil]

I cant really help you there. In EL4 each of the services are separate.
So a node can be part of the cluster but doesn't need to share the
resources such as a shared san disk. If you have the resources set up so
that it requires that resource, then it should be fenced. 


Robert Gil
Linux Systems Administrator
American Home Mortgage
Phone: 631-622-8410
Cell: 631-827-5775
Fax: 516-495-5861

-----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 12:24 PM
To: linux clustering
Subject: Re: [Linux-cluster] Cluster node without access to all
resources-trouble

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>

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