RPM & DNF Best Practices for Package Upgrade and Downgrade in Rocky Linux 8/9

Introduction

In modern Linux systems like Rocky Linux 8/9, managing software packages is an essential administrative task. The two most commonly used tools are RPM (Red Hat Package Manager) and DNF (Dandified YUM).
As a Senior Linux Administrator, you must not only know how to install, update, upgrade, and remove packages but also follow best practices to maintain security and stability of production systems.

Difference between RPM and DNF

• RPM: A low-level package manager that installs, removes, and verifies individual packages. It does not handle dependencies automatically.
• DNF: A high-level package manager that resolves dependencies automatically. It is the default package manager in Rocky Linux 8/9.

Best Practices for Package Upgrade & Downgrade

1. Check System Updates Safely

dnf check-update

This will show available updates without making changes.

2. Apply Security Updates Only

dnf updateinfo list security
dnf update --security -y

Always prioritize applying security patches before general updates to reduce system vulnerabilities.

3. Upgrade a Single Package

dnf upgrade <package-name>

Upgrades only the specified package, keeping the system stable.

4. Downgrade a Package

dnf downgrade <package-name>

This allows rolling back to an older version in case of compatibility issues.

5. Rollback with DNF History

dnf history list
dnf history undo <transaction-id>

Reverts changes made by a specific transaction, useful when an update causes issues.

6. Use Version Lock for Critical Packages

dnf install 'dnf-plugins-core'
dnf versionlock add <package-name>

This prevents critical packages from being accidentally upgraded.

7. Test Updates in Staging Before Production

Always validate new updates in a staging environment before applying them on production servers.

Security Considerations

• Enable automatic security updates where applicable.
• Regularly audit package versions against known CVEs (Common Vulnerabilities and Exposures).
• Use GPG signatures to verify package authenticity.
• Limit root access while performing upgrades.

Important Interview Preparation Tips (Linux Administrator)

1. Explain difference between RPM and DNF: Be ready to explain dependency management, rollback features, and version locking.
2. How to handle failed package updates? Mention usage of dnf history undo and dnf downgrade.
3. What are best practices for secure updates? Emphasize security patches first, staging environments, and GPG verification.
4. How do you ensure package stability in production? Version lock and proper testing procedures.
5. What steps do you take if a critical service fails after upgrade? Rollback, check logs, restore from backups if needed.

Conclusion

Using RPM and DNF efficiently is vital for every Linux administrator, especially in enterprise production environments.
By following these best practices for upgrade, downgrade, rollback, and security updates, you can ensure system reliability and security.
Additionally, understanding these concepts will help you excel in senior-level Linux administration interviews.