Caveats

If you use OpenJDK, you might find that Java no longer works: This issue is caused by missing symlinks in /etc/alternatives . The problem is caused by the OpenJDK package, and as a temporary workaround, you can use the following command:

rpm -qa --scripts java-{1.8.0,11}-openjdk-{headless,devel} | sed -n ,/postinstall/, /exit/{ /postinstall/! { /exit/ ! p} }' | sh

If your IPA server fails to run after the migration, use the following command (after fixing the Java issue mentioned above):

ipa-server-upgrade --skip-version-check

It is also worth checking the log file /var/log/migrate2rocky.log (Figure 3), which might contain errors the script encountered during the migration. There should be very few errors, but it is worth looking into each error to understand if anything needs fixing.

Figure 3: Reviewing the log file /var/log/migrate2rocky.log.

Conclusion

If you proceed according to instructions and take the necessary precautions, the migration from CentOS 8 to Rocky Linux 8 is a simple process – definitely easier than a manual upgrade between major versions. Given the fact that Rocky 8 will be supported until the end of May 2029, your server should be safe until then. However, if you are just running a few services and your configuration is fairly simple, you might want to consider setting up a new server based on the more modern Rocky Linux 9 and manually migrating the services one by one.

This article was made possible by support from CIQ through Linux New Media's Topic Subsidy Program (https://www.linuxnewmedia.com/Topic_Subsidy).