Switch from CentOS to Oracle Linux

This script is designed to automatically switch a CentOS instance to Oracle Linux by removing any CentOS-specific packages or replacing them with the Oracle Linux equivalent.

Supported versions

This script currently supports switching CentOS Linux 6, CentOS Linux 7 and CentOS Linux 8. It does not support CentOS Stream.

Before you switch

Remove all non-standard kernels i.e. kernels that are not from either the CentOS base or updates repos. Click for more info.

Because of the GRUB2 BootHole vulnerability, our SecureBoot shim can only boot kernels signed by Oracle and we can only replace the default CentOS kernels. While this may not have an impact if SecureBoot is currently disabled, enabling it at a later date could render the system unbootable. For that reason, we strongly recommend removing all non-standard kernels which includes the centosplus kernels.

1. Ensure your CentOS yum or dnf configuration is working, i.e. there are no stale repositories.
2. Disable all non-CentOS repositories. You can re-enable the repos after the switch.
3. Ensure you have at least 5GB of free space in /var/cache.
4. All automatic updates, e.g. via yum-cron should be disabled.

Usage

1. Login to your CentOS Linux 6, 7 or 8 instance as a user who has sudo privileges.
2. Either clone this repository or download the centos2ol.sh script.
3. Run sudo bash centos2ol.sh to switch your CentOS instance to Oracle Linux.

Usage options

• -r Reinstalls all CentOS RPMs with Oracle Linux RPMs

  If a system is swiched to Oracle Linux and there is no newer Oracle Linux version of a package already installed then the CentOS version remains. This option proceeds to reinstall any CentOS RPM with an identical version from Oracle Linunx. This is not necessary for support and has no impact to a systems functionality but is offered so a user can remove CentOS GPG keys from the truststore. A list of all non-Oracle RPMs will be displayed after the reinstall process.

• -V Verify RPM information before and after the switch

  This option creates four output files:

  • sorted list of installed RPMs before the switch
  • sorted list of installed RPMs after the switch
  • result of verification of all installed RPMs against the RPM database before the switch
  • result of verification of all installed RPMs against the RPM database after the switch

Limitations

1. The script currently needs to be able communicate with the CentOS and Oracle Linux yum repositories either directly or via a proxy.
2. The script currently does not support instances that are registered to a third-party management tool like Spacewalk, Foreman or Uyuni.
3. Compatibility with packages installed from third-party repositories is expected but not guaranteed. Some software doesn't like the existence of an /etc/oracle-release file, for example.
4. Packages that install third-party and/or closed-source kernel modules, e.g. commercial anti-virus products, may not work after switching.
5. The script only enables the base repositories required to enable switching to Oracle Linux. Users may need to enable additional repositories to obtain updates for packages already installed (see issue #1).

Debugging

Run sudo bash -x centos2ol.sh to switch your CentOS instance to Oracle Linux in debug mode. This will print a trace of commands and their arguments or associated word lists after they are expanded but before they are executed.

Get involved

We welcome contributions! See our contribution guidelines.

Support

• Open a GitHub issue for non-security related bug reports, questions, or requests for enhancements.
• To report a security issue or vulnerability, please follow the reporting security vulnerabilities instructions.

Resources

For more information on Oracle Linux, please visit https://www.oracle.com/linux.

License

Copyright (c) 2020 Oracle and/or its affiliates.

Licensed under the Universal Permissive License v 1.0 as shown at https://oss.oracle.com/licenses/upl/