Create new RHEL 8/9 systems

The first step to migrating from RHEL 7 to RHEL 8/9 is to create new RHEL 8/9 systems.

When creating these new systems, configure them according to your organization's requirements, based on your previous Salt infrastructure systems. If the choice allows, it is preferred to install RHEL 9 otherwise use RHEL 8.

Once created, install the Salt Minion agent on each system and connect it to a RHEL 7 Salt Master.

Perform these steps using Salt.

Note: The minionIDs used in the following examples are different than the minionIDs used in your environment.

Prerequisites

Before migrating to RHEL 8/9, you must be on RHEL 7.4 -7.9.

Procedure

1. Update the OS to ensure the most recent patches are applied to the new systems by running this command:

   salt \*rhel9 cmd.run ‘yum update -y’ 

2. Ensure dependencies are installed on all RHEL 9 servers:
   1. Openssl
   2. Epel-release
   3. Python3-cryptography (Python36-cryptography is not present in RHEL8)
   4. Python3-pyOpenSSL (Python36-pyOpenSSL is not present in RHEL8)
3. Disable the firewalld service or ensure ports 443, 4505, and 4506 are open for communiation between services. To disable the firewalld service, open a command, navigate to the new RHEL8/9 system, and run thse commands

   Systemctl stop firewalld
   Systemctl disable firewalld
   

4. To install dependencies:
   1. Create this state file and store it on the RHEL7 Salt Master system (where your RHEL 8/9 systems report) in the /srv/salt directory.

      # Install the dependencies for Salt install
      # file: /srv/salt/install_dependencies.sls
      # to apply this state run:
      # salt <minion_id> state.sls install_dependencies
      install_openssl:
        pkg.installed:
          - name: openssl
      
      install_codeready_repo:
        cmd.run:
          - name: subscription-manager repos --enable codeready-builder-for-rhel-9-$(arch)-rpms
          - require:
            - install_openssl
      
      install_epel:
        cmd.run:
          - name: dnf -y install https://dl.fedoraproject.org/pub/epel/epel-release-latest-9.noarch.rpm
          - require:
            - install_codeready_repo
      
      install_pycrypto:
        pkg.installed:
          - name: python3-cryptography
          - require:
            - install_epel
      
      install_pyopenssl:
        pkg.installed:
          - name: python3-pyOpenSSL
          - require:
            - install_pycrypto
      

   2. Run the install_dependencies.sls state command in test mode:

      Salt ‘*rhel9-*’ state.sls install_dependencies test=True

   3. If the state completed successfully without errors, run the command without test=true:

      Salt ‘*rhel9-*’ state.sls install_dependencies