Chapter 3. Converting to a RHEL system

This procedure describes the steps necessary to convert your system from CentOS Linux to Red Hat Enterprise Linux (RHEL).

If you are accessing RHEL packages using Red Hat CDN or Satellite through RHSM, there are two methods of registering and subscribing your system during the conversion:

  • Provide the organization ID and activation key. This method is preferred when converting many systems or when automating the conversion process using scripts. You must be the organization administrator to create an activation key. You must use this method if you are accessing RHEL packages using Satellite through RHSM.
  • Provide the username, password, and pool ID. Any user who is accessing RHEL packages using Red Hat CDN through RHSM or custom repositories can use this method.

Prerequisites

Procedure

  1. Start the Convert2RHEL utility.

    You can use Convert2RHEL with either RHSM or custom repositories.

    • Using RHSM:

      • With the organization ID and activation key:

        # convert2rhel --org organization_ID --activationkey activation_key

        Replace organization_ID and activation_key with the organization ID and the activation key from the Red Hat Customer Portal if you are using Red Hat CDN or the Satellite web UI if you are using Red Hat Satellite.

        Note

        If you are accessing RHEL packages using Satellite, you must use the organization ID and activation key to run the convert2rhel command.

      • With the username, password, and pool ID:

        # convert2rhel --username username --password password --pool pool_ID

        Replace username and password with your Red Hat Account credentials. Replace pool_ID with the pool ID of the subscription that you want to attach to the system. If you do not know the pool ID, omit the --pool option to generate a list of all subscriptions available for the account.

    • Using custom repositories:

      # convert2rhel --disable-submgr --enablerepo RHEL_RepoID1 --enablerepo RHEL_RepoID2

      Replace RHEL_RepoID with your custom repository configured in the /etc/yum.repos.d/ directory, for example, rhel-7-server-rpms or rhel-8-baseos and rhel-8-appstream.

      To display all available options, use the -h, --help option:

      # convert2rhel -h
  2. Before Convert2RHEL starts replacing packages from the original distribution with RHEL packages, the following warning message is displayed:

    The tool allows rollback of any action until this point.
    By continuing, all further changes on the system will need to be reverted manually by the user, if necessary.

    Changes made by Convert2RHEL up to this point can be automatically reverted. Confirm that you wish to proceed with the conversion process.

  3. Wait until Convert2RHEL installs the RHEL packages and finishes successfully.
  4. Recommended: If you used custom repositories for the conversion, register and subscribe your RHEL system. For more information, see How to register and subscribe a system offline to the Red Hat Customer Portal?.
  5. At this point, the system still runs with the original distribution kernel loaded in RAM. Reboot the system to boot the newly installed RHEL kernel.

    # reboot
  6. Remove third-party packages from the original OS that remained unchanged (typically packages that do not have a RHEL counterpart). To get a list of these packages, use:

    # yum list extras --disablerepo="*" --enablerepo=RHEL_RepoID

    Replace RHEL_RepoID with your repository.

Verification

  • Verify that your system operates as expected. If necessary, reconfigure system services after the conversion and fix dependency errors. For more information, see Fixing dependency errors.