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 and architectures

This script currently supports switching CentOS Linux 6, CentOS Linux 7 and CentOS Linux 8 on both

x86_64

aarch64

Support for switching

aarch64

hosts should be considered experimental due to limited testing. Please ensure you have a complete working backup before attempting to switch and report any issues you encounter during the process.

Before you start

IMPORTANT: this script is a work-in-progress and is not designed to handle all possible configurations. Please ensure you have a complete working backup of the system before you start this process in the event the script is unable to convert the system successfully or unable to rollback the changes it made.

Remove all non-standard kernels

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, i.e. any kernel that is installed that is not provided by either the

base

updates

centosplus

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 switched 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 Linux. 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.

• -k

  Do not install the UEK kernel and disable UEK repos

This option will not install the UEK kernel and will disable all UEK yum repositories.

• -V

  Verify RPM information before and after the switch

This option creates four output files in

/var/tmp/

• ${hostname}-rpms-list-[before|after].log

  : a sorted list of installed packages

  before

  and

  after

  the switch to Oracle Linux.

• ${hostname}-rpms-verified-[before|after].log

  : the RPM verification results for all installed packages

  before

  and

  after

  the switch to Oracle Linux.

Testing

See

TESTING.md

Known issues

1. There is a reported issue with the upstream OpenJDK package resetting the

   alternatives

   configuration during a

   dnf reinstall

   transaction.

We recommend recording the output of

alternatives --list

centos2ol.sh

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

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 oracle.com/linux.

License

Copyright (c) 2020, 2021 Oracle and/or its affiliates.

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