KubeControllerManagerDown

Meaning

KubeControllerManager has disappeared from Prometheus target discovery.

Impact

The cluster is not functional and Kubernetes resources cannot be reconciled.

Full context

More about kube-controller-manager function can be found at https://kubernetes.io/docs/reference/command-line-tools-reference/kube-controller-manager/

Diagnosis

TODO

Mitigation

See old CoreOS docs in Web Archive