[Linux-cluster] RHCS 5.1 latest packages, 2-node cluster, doesn't come up with only 1 node

[Celso K. Webber]

Hi Lon,

On Fri, 08 Feb 2008 16:15:36 -0500, Lon Hohberger wrote
> On Fri, 2008-02-08 at 11:18 -0200, Celso K. Webber wrote:
> > Feb  7 20:07:01 mrp02 kernel: dlm: no local IP address has been set
> > Feb  7 20:07:01 mrp02 kernel: dlm: cannot start dlm lowcomms -107
> 
> This is why rgmanager didn't work (and possibly even exited).  Does
> 'uname -n' match what's in cluster.conf?
> 
No, it does not! I didn't know it should match, I'm configuring RHCS Clusters 
since version 2.1 and this never bothered me, sorry!!!

Well, I usually do the following in /etc/hosts:
-> assume network 192.168.1.0/24 is for public access
-> assume network 10.0.0.0/8 is for heartbeat

192.168.1.1   realservername1.domainname realservername1
192.168.1.2   realservername2.domainname realservername2

10.0.0.1      node1.localdomain node1
10.0.0.2      node2.localdomain node2

192.168.1.3   servicename1.domainname servicename1
192.168.1.4   servicename2.domainname servicename2
... and so on for other virtual IPs for services ...

Then I configure in cluster.conf the names associated with the private 
addresses/interfaces, so that I'm sure that heartbeat traffic is going 
through the correct interfaces.

For obvious reasons, "uname -n" returns the public hostnames, such as 
realservername1.domainname.

I noticed that from some time there is a question in the FAQ explaining how 
to "bind" the heartbeat traffic to a specific interface/address. But I was 
happy with my solution, specially because the answer to that question 
suggested touching the init script, and I don't like to alter standard system 
files, specially init scripts. At least in RHCS v4, I didn't find a better 
way to "bind" the heartbeat traffic to a specific interface. I didn't 
experiment about this with RHCS v5, I just went on with my previous method.

For me this is common practice, for instance, Oracle Database respects an 
environment variable called ORACLE_HOSTNAME, so that you can "instruct" the 
several utilities to consider that name instead of the real server's name. 
This is very useful in a Cluster environment.

Please tell me:
* is it really wrong set the node names in cluster.conf to a name different 
to that reported by "uname -n"?
* if it is "ugly" or considered wrong, what is the best way to instruct CMAN 
which interface to use for heartbeat?
* does this solution work both for RHCS v4 and v5?
* would it be better to have only one interface for public and heartbeat 
traffic, maybe channel bonding dual NICs?
* is there any other significant difference between RHCSv4 and v5 I should be 
aware of?

As always, thank you very very much for your support!

Regards,

Celso.
-- 
*Celso Kopp Webber*

celso at webbertek.com.br <mailto:celso at webbertek.com.br>

*Webbertek - Opensource Knowledge*
(41) 8813-1919 - celular
(41) 4063-8448, ramal 102 - fixo


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