[CentOS] Upgrade Question

Tue Jan 10 21:16:00 UTC 2012
Les Mikesell <lesmikesell at gmail.com>

On Tue, Jan 10, 2012 at 1:35 PM,  <m.roth at 5-cent.us> wrote:
>
>> We've got about 200 existing servers running CentOS/RHEL 5.6 and all new
>> servers are being provisioned using CentOS/RHEL 6.1.  So that everything
>> is consistent we need to upgrade the servers running CentOS/RHEL 5.6. I've
>> searched the CentOS wiki, the Red Hat site, and the internet  looking for
>> something official on upgrading/migrating from CentOS/RHEL 5.x to
>> CentOS/RHEL 6.x.  There's got to be a way other than having 2 times
>> hardware.
>>
>> Any ideas???
>
> What we do is build one, then create /boot/new and /new on the next
> server, rsync over to them, then mkdir /boot/old and /old, and (using zsh
> with modules loaded) mv * old, mv old/lost+found ., mv old/new/* ., make
> sure a few things are correct (for example, ifcfg-eth*, /etc/ssh/), and
> sync, then reboot. All your other stuff is fine....

Have you looked at http://rear.sourceforge.net/ (and in EPEL) as a
potential backup/clone/rollout mechanism?  It seems like something
that might suit your sensibilities, but I'm not sure what kind of
contortions you would need to do to boot into its recovery image
remotely.    For anyone too lazy to look, it builds a bootable iso
containing your own current system's tools to re-install itself,
recreating the filesystem (LVM/raid/partitions) and dropping in a
backup that can be included or separate.  It is intended for mostly
automated restores back onto the same system but I think it can be
abused for cloning and there is a point where you can adjust the
filesystem layout.

-- 
   Les Mikesell
     lesmikesell at gmail.com