[Linux-cluster] centos5 to RHEL6 migration

Digimer linux at alteeve.com
Mon Jan 9 02:38:34 UTC 2012

On 01/08/2012 06:39 PM, Terry wrote:
> Hello,
> I am trying to gently migrate a 3-node cluster from centos5 to RHEL6.  I
> have already taken one of the three nodes out and rebuilt it. My
> thinking is to build a new cluster from the RHEL node but want to run it
> by everyone here first. The cluster consists of a handful of NFS volumes
> and a PostgreSQL database.  I am not concerned about the database.  I am
> moving to a new version and will simply migrate that.  I am more
> concerned about all of the ext4 clustered LVM volumes.  In this process,
> if I shut down the old cluster, what's the process to force the new node
> to read those volumes in to the new single-node cluster?  A pvscan on
> the new server shows all of the volumes fine. I am concerned there's
> something else I'll have to do here to begin mounting these volumes in
> the new cluster.
> [root at server ~]# pvdisplay
>   Skipping clustered volume group vg_data01b
> Thanks!

  Technically yes, practically no. Or rather, not without a lot of
testing first.

  I've never done this, but here are some pointers;

<cman upgrading="yes" disallowed="1" ...>

	Set this if you are performing a rolling upgrade of the cluster
	between major releases.

	Set this to 1 enable cman's Disallowed mode. This is usually
	only needed for backwards compatibility.

<group groupd_compat="1" />

	Enable compatibility with cluster2 nodes. groupd(8)

  There may be some other things you need to do as well. Please be sure
to do proper testing and, if you have the budget, hire Red Hat to advise
on this process. Also, please report back your results. It would help me
help others in the same boat later. :)

E-Mail:              digimer at alteeve.com
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