OpenShift Nodes Explained¶
Introduction¶
Node maintenance in OpenShift uses cordon and drain to move workloads before repair or reboot. Always check DaemonSets, local storage, and PodDisruptionBudgets before draining.
Core Concepts¶
OpenShift builds on Kubernetes with projects, Routes, ImageStreams, Builds, Operators, SCCs, and integrated platform administration.
Practical Examples¶
oc get nodes
oc adm cordon worker-1
oc adm drain worker-1 --ignore-daemonsets --delete-emptydir-data
oc adm uncordon worker-1
Example output:
node/worker-1 cordoned
node/worker-1 drained
node/worker-1 uncordoned
Verification¶
oc get nodes
oc get pods -A --field-selector spec.nodeName=worker-1
oc get pdb -A
Common Mistakes¶
- Draining without checking PodDisruptionBudgets.
- Forgetting to uncordon after maintenance.
- Deleting static or mirror pods manually.
Quick Checklist¶
- Confirm the active project.
- Inspect the exact object named in the error.
- Read recent events.
- Apply one focused fix.
- Verify status after the change.
Related Guides¶
Summary¶
OpenShift Nodes Explained is best understood through the OpenShift objects involved and the oc commands that verify their current state.