After applying a patch, which step ensures the patch did not adversely affect the system?

• A. Reboot
• B. Verify Full System Functionality
• C. Document Changes
• D. Roll Back

Answer: (B)

After applying a patch, the essential step is to verify full system functionality. This means checking that all critical services start correctly, security controls remain intact, performance stays within expected levels, and dependent systems or integrations operate as they should. This verification catches regressions, incompatibilities, or subtle changes in behavior that the patch might introduce, ensuring the system remains healthy before resuming normal operations. Rebooting might be needed for the patch to take effect, but it does not by itself confirm everything still works. Documenting changes is about traceability, not testing functionality, and rolling back is something you do if verification reveals problems. In cloud environments, this verification also includes validating workloads, service endpoints, and automation scripts to ensure the patch didn’t disrupt automated processes.