An Introduction to Convert2RHEL: Now officially supported to convert RHEL-like systems to RHEL

Convert2RHEL is now an officially supported component of Red Hat Enterprise Linux (RHEL). Convert2RHEL enables the conversion of select RHEL derivative distributions into a supportable RHEL system, retaining existing applications and configurations. This is the culmination of multiple teams within Red Hat who have worked to provide solutions and guidance to our customers and the community at large. 

The concept for the Convert2RHEL utility began nearly five years ago when Red Hat engineering was asked to explore how conversions to RHEL might work. Since then, it has evolved as a collaborative effort between Red Hat Engineering and Consulting services, who have used it successfully with many Oracle Linux and CentOS Linux conversions in many large and complex enterprise environments. Due to numerous requests, Red Hat has now productized it as a supported component of RHEL. 

It was important to ensure that access to the Convert2RHEL utility was frictionless and served the broad CentOS Linux user community who wanted to make use of new options such as our no-cost developer subscriptions. In January, Red Hat announced the enhanced no-cost Red Hat Developer Subscription for Individuals and the Developer for Teams subscription (available via sales), which both provide no-cost access to RHEL subscriptions. This includes Red Hat Insights and many management capabilities from cloud.redhat.com. 

What’s new with Convert2RHEL

Official Red Hat utility - Convert2RHEL is officially supported as a self-service utility for conversions of CentOS Linux 7 and 8 to RHEL.  Support for converting to RHEL from Oracle Linux 7 and 8 is also available as of June 2021^[1]. More details are provided in the Red Hat Customer support policy.

Conversion guidance - We have released official documentation for users who are converting from an RPM-based Linux distribution to Red Hat Enterprise Linux 8, and there is a public-facing Red Hat Enterprise Linux migration process landing page to help guide your journey. Existing RHEL customers can check out the Migration Center in the Red Hat Customer Portal for additional resources as well as a new Convert2RHEL FAQ. We recommend that those with complex migration projects or those wanting to accelerate their migration engage Red Hat Consulting services experts to help them convert key applications and workloads.

Accessibility - Access Convert2RHEL from a yum compatible repository at Red Hat's FTP server. There is no paywall and no subscription is required to access the Convert2RHEL utility and its updates. However, a subscription is required to access RHEL content to complete a conversion. 

Flexibility - Convert2RHEL can now access RHEL content via multiple methods depending on your use case. We provide multiple network access methods using Red Hat Subscription Manager, Red Hat Satellite, or other mirrored repositories.  

Stability - We have included many fixes and minor enhancements in the most recent release of Convert2RHEL. For example, a built-in inspection check was added for untested third party drivers to prevent compatibility risk. Plans for later releases include an override option to enable the utility to proceed after independent testing. 

The future of Convert2RHEL

We are actively exploring other capabilities and enhancements, which we plan to share in future releases. Note that Convert2RHEL performs an in-place conversion of RHEL derived Linux distributions such as CentOS Linux and Oracle Linux. We will evaluate future compatibility with other RHEL derivative operating systems in the future based on user demand. 

This utility does not convert from other Linux distributions such as SUSE, Debian or Ubuntu to RHEL at this time due to technical concepts such as filesystem metadata and technologies, configuration, and application user space compatibility. If you need to migrate or convert these types of systems, reach out to Red Hat Consulting services and they can provide assistance.

Quick start for simple use cases 

Be sure to read the official documentation for important guidance, additional features, and information on known limitations. It is important to assess the critical nature of the applications and data on a system before making significant changes. A simple test or development environment may require less assessment than a critical database server, for example. 

If you feel you need assistance with assessing your environment’s complexity or performing large scale conversions, Red Hat Consulting services can provide assistance.  Additionally, the use of third party kernel modules such as graphics or storage drivers may require additional testing and planning. The documentation provides additional guidance on what precautions should be made before proceeding.  There are numerous features such as support for rollbacks up to a certain point in the process, use of Activation Keys instead of credentials, and pulling RHEL content from Red Hat Satellite or other repository management solutions.

For a simple CentOS Linux system that is only using the CentOS or EPEL repositories, the following quick start instructions will demonstrate how quickly and easily the utility can convert a system to RHEL. This example demonstrates installing and using Convert2RHEL in a simple CentOS Linux environment over the network to pull the latest RHEL packages using Subscription Manager.

Download the Red Hat GPG key.

# curl -o /etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release https://www.redhat.com/security/data/fd431d51.txt

After downloading the GPG key, you also need to download the certificate.

# curl --create-dirs -o /etc/rhsm/ca/redhat-uep.pem https://ftp.redhat.com/redhat/convert2rhel/redhat-uep.pem

Install the Convert2RHEL repository, replacing VERSION_NUMBER with the appropriate major version of the OS, for example 7 or 8.

# curl -o /etc/yum.repos.d/convert2rhel.repo https://ftp.redhat.com/redhat/convert2rhel/VERSION_NUMBER/convert2rhel.repo

Install the Convert2RHEL utility. Then run it with -h to see all options

# yum -y install convert2rhel
# convert2rhel -h

Run Convert2RHEL to begin the conversion process and automatically register to Subscription Manager. The -y option can be used after testing to auto-answer yes for known, tested scenarios. Additional capabilities such as using Activation Keys instead of sensitive credentials are explained in the documentation.

# convert2rhel --auto-attach --username=USERNAME --password=PASSWORD

Note 1:  An unsupported, proof of concept Ansible Playbook can be found at https://github.com/oamg/convert2rhel/blob/main/ansible/ansible-convert2rhel.yml  which demonstrates how to automate these steps at scale.

Note 2: While not supported by Red Hat due to version 6 being outside of the maintenance phase of the life cycle, guidance for conversions from CentOS Linux 6 and Oracle Linux 6 is provided in How to convert from CentOS Linux 6 or Oracle Linux 6 to RHEL. Guidance is provided for upgrading from RHEL 6 to RHEL 7 on the Red Hat Customer Portal. 

Conversion success 

Once the conversion succeeds, a reboot is required to start the system as a Red Hat Enterprise Linux system. It may be necessary to re-install third-party RPMs or otherwise re-configure some system services after conversion. Another benefit to converting systems to RHEL is to take advantage of the in-place upgrades from RHEL 7 to RHEL 8.  If you encounter any bugs with the Convert2RHEL utility itself, or would like to request additional feature enhancements, please open a ticket using the respective links for RHEL 7 or RHEL 8.