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This alert fires when a node is stuck in the drain process for more than the set amount of time. Default is 10 minutes.

This can hold up the maintenance process and delay the upgrade of the cluster.

Steps for debugging

Nodes usually get stuck in the drain process when there is a pod that isn’t evictable. This can be caused by a (rogue) PodDisruptionBudget, pods on new nodes not entering a Ready state, or extremely long terminationGracePeriodSeconds among other things.

Check operator logs

The drain process on OpenShift is initiated by the machine-config-operator. The operator logs reasons for why a node isn’t draining. You can find these logs by running the following command:

kubectl -n openshift-machine-config-operator logs deployments/machine-config-controller

Look out for messages like the following:

E0116 14:26:30.051014       1 drain_controller.go:110] error when evicting pods/"apiserver-786c87d87d-9lkxw" -n "openshift-oauth-apiserver" (will retry after 5s): Cannot evict pod as it would violate the pod's disruption budget.

Add the PodDisruptionBudget found to cause the issue to the maintenance log.

Create a customer ticket to get the PodDisruptionBudget fixed if possible.

Check pods on node

You can list the pods on the node by running the following command:

kubectl get pods --all-namespaces --field-selector spec.nodeName=$NODE_NAME

Check for pods (for example database pods) that might lead to data loss if evicted.

Force drain the node

If the node is stuck in the drain process for a long time, you can force the drain by running the following command:

kubectl drain --force --ignore-daemonsets --delete-emptydir-data --grace-period=30 $NODE_NAME

This can lead to data loss depending on the application. Check pods left on node first.


If this alert isn’t actionable, noisy, or was raised too early you may want to tune the time until the alert fires. You can do this by changing the for parameter in the NodeDrainStuck alert configuration.