Managing CentOS Migrations and RHEL Upgrades

Instructions

In a previous activity, you tested a sample application and converted the servera machine from CentOS Linux 7 to RHEL 7. In this activity, you verify that the server is converted as expected. Then, you test the sample application to confirm that it still executes successfully.

1. On the servera machine, verify that the operating system is now RHEL 7.

   1. Log in to the servera machine as the student user. Switch to the root user. Use student as the password.

      [student@workstation ~]$ ssh servera
      student@servera's password: student
      [student@servera ~]$ sudo -i
      [sudo] password for student: student
      [root@servera ~]#

   2. Confirm the release of the operating system. Review the contents of the /etc/redhat-release file.

      [root@servera ~]# cat /etc/redhat-release
      Red Hat Enterprise Linux Server release 7.9 (Maipo)

   3. Verify that the kernel that is loaded by the operating system is a RHEL 7 kernel. A RHEL 7 kernel contains the string el7 as a reference to Enterprise Linux 7.

      [root@servera ~]# uname -a
      Linux servera.example.com 3.10.0-1160.108.1.el7.x86_64 #1 SMP Thu Jan 4 14:55:32 EST 2024 x86_64 x86_64 x86_64 GNU/Linux

      Note

      If the operating system is not RHEL, then reboot the servera system by using the reboot command and perform Step 1 again.

2. Review the logs that were generated by the conversion to identify potential issues.

   1. Confirm the creation of the /var/log/convert2rhel directory and the convert2rhel.log, the rpm_va.log, and the rpm_va_after_conversion.log log files.

      [root@servera ~]# ls -ld /var/log/convert2rhel/
      drwxr-xr-x. 3 root root 177 Feb  1 11:03 /var/log/convert2rhel/
      [root@servera ~]# ls -l /var/log/convert2rhel/
      total 88
      drwxr-xr-x. 2 root root    88 Feb  1 10:56 archive
      -rw-r--r--. 1 root root 68773 Feb  1 11:03 convert2rhel.log
      -rw-r--r--. 1 root root  5563 Feb  1 11:03 convert2rhel-pre-conversion.json
      -rw-r--r--. 1 root root  1003 Feb  1 11:03 convert2rhel-pre-conversion.txt
      -rw-r--r--. 1 root root   260 Feb  1 11:03 rpm_va_after_conversion.log
      -rw-r--r--. 1 root root   260 Feb  1 10:56 rpm_va.log

   2. Verify that the conversion completed with success in the /var/log/convert2rhel/convert2rhel.log log file.

      [root@servera ~]# cat /var/log/convert2rhel/convert2rhel.log
      ...output omitted...
      
      Conversion successful!
      
      WARNING - In order to boot the RHEL kernel, restart of the system is needed.
      [2024-02-01T11:03:35+0000] DEBUG - /var/run/lock/convert2rhel.pid PID 11075 unlocked.

   3. Confirm that discrepancies in package verification did not increase after conversion. Use the diff command to find differences between the /var/log/convert2rhel/rpm_va_after_conversion.log and the /var/log/convert2rhel/rpm_va.log log files.

      [root@servera ~]# diff -y /var/log/convert2rhel/rpm_va_after_conversion.log \
      /var/log/convert2rhel/rpm_va.log
      					>	S.5....T.  c /etc/sysconfig/authconfig
                      			>	S.5....T.  c /etc/rhsm/rhsm.conf
      ....L.... c /etc/pam.d/fingerprint-auth	....L....  c /etc/pam.d/fingerprint-auth
      ....L.... c /etc/pam.d/password-auth	....L....  c /etc/pam.d/password-auth
      ....L.... c /etc/pam.d/postlogin	....L....  c /etc/pam.d/postlogin
      ....L.... c /etc/pam.d/smartcard-auth	....L....  c /etc/pam.d/smartcard-auth
      ....L.... c /etc/pam.d/system-auth	....L....  c /etc/pam.d/system-auth
      S.5....T. c /etc/rhsm/rhsm.conf	        <
      S.5....T. c /etc/sysconfig/authconfig	<

      Differences exist between the two log files, but nothing indicates errors or unexpected changes.

   4. Review the conversion log. Inspect the log of the last run of the convert2rhel command, which is in the /var/log/convert2rhel/archive directory.

      [root@servera ~]# ls -l /var/log/convert2rhel/archive/
      total 108
      -rw-r--r--. 1 root root 43603 Feb  1 10:36 convert2rhel-20240201T163658Z.log
      -rw-r--r--. 1 root root 62982 Feb  1 10:49 convert2rhel-20240201T164940Z.log
      [root@servera ~]# cat \
      /var/log/convert2rhel/archive/convert2rhel-20240201T164940Z.log
      ...output omitted...
      
      (SUCCESS) RHEL_COMPATIBLE_KERNEL::SUCCESS - N/A
      (SUCCESS) TAINTED_KMODS::SUCCESS - N/A
      (SUCCESS) DBUS_IS_RUNNING::SUCCESS - N/A
      (SUCCESS) ENSURE_KERNEL_MODULES_COMPATIBILITY::SUCCESS - N/A
      (SUCCESS) INSTALL_RED_HAT_GPG_KEY::SUCCESS - N/A
      (SUCCESS) INSTALL_RED_HAT_CERT_FOR_YUM::SUCCESS - N/A
      (SUCCESS) CONVERT2RHEL_LATEST_VERSION::SUCCESS - N/A
      
      ========== Info (No changes needed) ==========
      (INFO) REMOVE_REPOSITORY_FILES_PACKAGES::REPOSITORY_FILE_PACKAGES_REMOVED - Repository
           file packages to be removed
           Description: We have identified installed packages that match a pre-defined
           list of packages that are to be removed during the conversion
           Diagnosis: The following packages will be removed during the conversion:
           centos-release-7-9.2009.1.el7.centos.x86_64
           Remediation: N/A
      (INFO) REMOVE_EXCLUDED_PACKAGES::EXCLUDED_PACKAGES_REMOVED - Excluded packages to
           be removed
           Description: We have identified installed packages that match a pre-defined
           list of packages that are to be removed during the conversion
           Diagnosis: The following packages will be removed during the conversion:
           centos-logos-70.0.6-3.el7.centos.noarch
           Remediation: N/A
      (INFO) DBUS_IS_RUNNING::DBUS_IS_RUNNING_CHECK_SKIP - Skipping the dbus is running
           check
           Description: Skipping the check because we have been asked not to subscribe
           this system to RHSM.
           Diagnosis: N/A
           Remediation: N/A
      
      [2024-02-01T10:49:40+0000] DEBUG - /var/run/lock/convert2rhel.pid PID 10523 unlocked.

3. Confirm that the demo application continues to work as expected.

   1. On the workstation machine, open a browser and navigate to the http://servera.lab.example.com site. Wait for the application to start.

   2. When the application finishes loading, press Space or click the web page to start playing. Press Space to prevent the bird from falling.

   3. Exit the demo application when you finish your game.

4. Exit the servera machine.

   [root@servera ~]# exit
   logout
   [student@servera ~]$ exit
   logout
   Connection to servera closed.