Before we started to use Oracle Linux for running our Oracle installations on we had created a few RHEL hosts, I’ve been wanting to switch them from Redhat to Oracle Linux but never found the time as I imagined I would have to re-install the OS from scratch.

I discovered that this isn’t the case after a bit of internet research. Oracle does tout an easy way to switch but that involves having a valid ULN support contract which we don’t have, however there is a method of switching without one it’s just not very well documented.

Using the notes Here as a guide I formulated the following steps :

1. Get the PGP key for ol6:

   wget https://public-yum.oracle.com/RPM-GPG-KEY-oracle-ol6 -O /etc/pki/rpm-gpg/RPM-GPG-KEY-oracle

2. Get the OL6 repo:

   cd /etc/yum.repos.d wget https://public-yum.oracle.com/public-yum-ol6.repo

3. Rename the rhel-source.repo in /etc/yum.repos.d:

   mv rhel-source.repo rhel-source.repoold

4. Disable the presto and rhnplugin plugins by setting the enabled flag to 0 in :

   vi /etc/yum/pluginconf.d/presto.conf vi /etc/yum/pluginconf.d/rhnplugin.conf

5. Have to remove the libreport.x86_64 package as this will cause the process to fail, it doesn’t exist on the other OL6 hosts so should be safe to remove:

   yum erase libreport

6. Test with yum list updates, it should run and return a list of packages if the changes have been successful then do a yum upgrade. If the yum list updates fails do a yum clean all to delete any existing yum information and do the yum list updates again

7. Remove the file public-yum-ol6.repo-disabled from /etc/yum.repo.d and rename the file public-yum-ol6.repo.rpmnew to public-yum-ol6.repo:

   rm /etc/yum.repos.d/public-yum-ol6.repo-disabled mv /etc/yum.repos.d/public-yum-ol6.repo.rpmnew /etc/yum.repos.d/public-yum-ol6.repo

8. Install the Unbreakable Kernel:

   yum install kernel-uek kernel-uek-devel

9. Edit grub.conf to use unbreakable kernel:

   vi /boot/grub/grub.conf

   change default to 0

10. Reboot