Upgrading Red Hat OpenShift isn’t just about running oc adm upgrade. Behind the scenes, a carefully orchestrated process ensures your cluster stays available while everything gets updated. In this guide, I’ll walk through: Real Upgrade path 4.19 to 4.20 Handling AdminAckRequired blockers Setting upgrade channels properly Understanding how OpenShift upgrades nodes (masters + workers) Why Pod Disruption Budgets (PDBs) can make or break your upgrade Pre-Upgrade : Check that none of the operators are "Degraded" Check PDB's. Check Failing Pods. Run a must gather (oc adm must-gather). 1. Check current status #oc adm upgrade Enter fullscreen mode Exit fullscreen mode The output will look something like: Cluster version is 4.19.27 Upgradeable=False Reason: AdminAckRequired Message: The admissionregistration.k8s.io/v1beta1 group version is deprecated in 4.19 and will be removed in 4.20.Any clients using the v1beta1 version of these resources must be updated to use the corresponding v1 version instead.…