Converting a Red Hat Linux 5.8 install to CentOS

Recently, we wanted to convert from Red Hat Enterprise Linux to CentOS. CentOS is a build of Red Hat Enterprise Linux from all of the open source packages that are released by Red Hat. There are a number of instructions in this regard, but the overall process is the same. My conversion was a Red Hat Enterprise Linux 5.8 to CentOS 5.8.

I started by following these instructions from saylinux.net (or thuannvn.blogspot.com). However, I had to adjust the instructions for RHEL 5.8 – just look in the directory on mirror.centos.org for the proper version of the packages you need. You won’t be able to use yum to download the packages because you want to pull not from RHEL but from CentOS – and yum will be getting updated as well.

Firstly, do a cleanup:

yum clean all

Then, create a working space where RPMs can be downloaded:

mkdir ~/centos
cd ~/centos

Now download the relevant CentOS key and import it:

wget http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
rpm --import RPM-GPG-KEY-CentOS-5

Then, get relevant packages from CentOS – note these instructions will pull i386 packages or x86_64 packages depending on your system:

wget http://mirror.centos.org/centos/5/os/`uname -m`/CentOS/centos-release-5-8.el5.centos.i386.rpm
wget http://mirror.centos.org/centos/5/os/`uname -m`/CentOS/centos-release-notes-5.8-0.i386.rpm
wget http://mirror.centos.org/centos/5/os/`uname -m`/CentOS/yum-3.2.22-39.el5.centos.noarch.rpm
wget http://mirror.centos.org/centos/5/os/`uname -m`/CentOS/yum-updatesd-0.9-2.el5.noarch.rpm
wget http://mirror.centos.org/centos/5/os/`uname -m`/CentOS/yum-fastestmirror-1.1.16-21.el5.noarch.rpm

You don’t have to use wget either; you could – if you want – instead use a text browser like elinks to get the same packages. Using elinks allows you to get the most recent version without stumbling over the version number – if the package is updated, you don’t have to guess at the version numbers in the filename.

elinks http://mirror.centos.org/centos/5/os/`uname -m`/CentOS/

Delete unnecessary packages from RHEL – in particular, those that use the Red Hat Network (RHN):

rpm -e yum-rhn-plugin rhn-client-tools rhn-setup rhn-check rhnsd

If there are any other packages that require yum-rhn-plugin or related packages, add it to the list of packages to remove.

Now update all of the packages that were downloaded:

rpm -Uvh --force *.rpm

Lastly, perform an upgrade to fully update the system from the new CentOS repositories:

yum upgrade

For best practices, you probably should reboot here as well – thus loading new libraries, deleting old files, and activating new kernels.

Red Hat Enterprise Linux 3 Approaches End-of-Life

Red Hat Enterprise Linux 3 will be end-of-life on 31 October 2010 (about six months away). Red Hat gives details about their product lifecycle on their web site.

RHEL 4 will reach end-of-life on 29 February 2012, and RHEL 5 will reach end-of-life on 31 March 2014 – so for them, there is several years left. The CentOS distributionCentOS distribution has CentOS 4 and 5 available for download – CentOS is an open source build of Red Hat Enterprise Linux.

RHEL 6 entered beta a little while ago, and is available for testing. CentOS 6 does not seem to exist yet.

BARcamp Chicago!

Got back from BARcamp Chicago Sunday night. It was a good time, and had a lot of good workshops. Met some good people, and used the nice high-speed bandwidth (but had to bypass the slow DNS!).

If you want an excellent DNS service, fast and unrestricted, use OpenDNS. This service also offers phishing protection, abbreviations, and spell-correction.

At BARcamp, some folks went to sleep – and some did not (like yours truly…). Several brought sleeping bags and went to sleep.

There were talks on Testing, the Bayes Theorem, Groovy, LISP, the rPath Linux distribution and Conary, and more. There was also the “InstallFest” – Linux installs made easy with help on hand. Even so, my machine was maxed out with CentOS 3 (a Red Hat 2.1AS source-compiled distro), even though I did upgrade it to CentOS 3.8. My machine is probably memorable as it had to be the oldest machine present (a Pentium-150 IBM Thinkpad) – and had no graphical interface – at least, on the machine itself. The graphical interface on the Thinkpad 760XL is rather odd – the full screen is used by “stretching” the actual display to the full size; otherwise, it only takes up about 75% of the LCD display space.

It was interesting to see (at BARcamp) that the Mountain Dew disappeared and was hard to get at the end, while there was plenty (plenty!) of Red Bull left. We know which is favored….

Next up is the Chicago Linux Group (which also hosts the Chicago Lisp Group), as well as the Madison LOPSA chapter meeting.