CentOS 4 to 5 upgrade

newuser455 · 04-12-2007, 10:58 PM

Does anyone know how to upgrade form CentOS 4 to CentOS 5? I tried following the instructions in the release announcement which are as follows:

Quote:

The best way to move from CentOS-4 to CentOS-5 is via an installer
upgrade. However if you must do it online, here are some tips to help:
- Remove as many packages as you can, strip it right back to the
original OS if possible
- Backup everything
- Disable all repositories, except the centos-5 OS and Updates repos
- init 3
- shutdown as many services as possible
- download and install the centos-release-5.x rpm, which will update
your yum configs
- run a yum upgade ( not update )

However, when I ran yum upgrade, I got a bunch of messages telling me that certain packages were not compatible with the kernel.

For now, I just install the centos-release-4.4 package again which fixed yum. Anyone have any ideas?

reddazz · 04-14-2007, 08:12 AM

Personally, I would install the centos-release rpm for CentOS 5 first and then do

Code:

#yum upgrade yum kernel

After that I would reboot and select the new kernel and then do

Code:

#yum -y upgrade

Lenard · 04-14-2007, 08:13 AM

If you have read and followed the first tip;

- Remove as many packages as you can, strip it right back to the original OS if possible

the yum upgrade will work. A lot of the third party replacement rpm packages (and there dependencies) are problematic when doing any major version upgrade. Best advice is to back up the entire /etc directory and any important personal data and settings then do a clean wipe and load install. Red Hat also advices not to do an update/upgrade installation and to do a fresh clean new installation.

I'm not saying it cannot be done, but it takes some planning, preparation and time before attempting the upgrade. The backup of the entire /etc directory and important personal data and settings is always a good idea in any case.

I upgraded my systems from CentOS-4.4 (with custom packages installed) to RHEL5, took about three hours and a half total for each system. Most of that time was for making a backup and cleaning the systems from conflicting third party packaging out, only about 20 minutes was used for the upgrade. Some third party packaging (KDE 3.5.6 for example) remained in place for the upgrade and did not cause an issue.

It is advisable to also have any third party repos reconfigured to the new version of the OS before starting the yum upgrade path. It is almost impossible to upgrade the OS and not upgrade the third party packaging.

newuser455 · 04-14-2007, 02:43 PM

Thanks for the help. All of the packages I have installed are from either the centos base repo or the dag weeirs repo, so I don't think I need to remove any packages.

Lenard · 04-14-2007, 06:47 PM

Yes, even rpm packages from Dag's repo can be a problem. Best idea install/upgrade the rpmforge-release package.

http://dag.wieers.com/rpm/FAQ.php#B