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oracle
230 Stars 51 Forks Universal Permissive License v1.0 31 Commits 14 Opened issues

Description

Script and documentation to switch CentOS Linux to Oracle Linux

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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
and
aarch64
architectures. It does not support CentOS Stream.

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
or
updates
repo. This 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 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
for instructions on the available tests and how to run them.

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
prior to running
centos2ol.sh
and reviewing the same output after switching. If you experience an issue with a package other than OpenJDK, please open an issue

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

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/

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