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Determining the kube-scheduler and kube-controller-manager leader for troubleshooting

Jena Miller
  • Updated

Overview/Background

Certain Kubernetes components, namely the kube-scheduler and kube-controller-manager, have the concept of a leader. When troubleshooting these components, it can be useful to know which instance is the leader, as only the current leader will log associated actions and events.

Solution

After a leader election has taken place and a leader has been determined for the kube-scheduler and/or kube-controller-manager, the leader (holderIdentity) is saved in its respective endpoint. As such, we can use kubectl to find the current leader.

kube-scheduler

To find the kube-scheduler leader using kubectl:

kubectl -n kube-system get endpoints kube-scheduler -o jsonpath='{.metadata.annotations.control-plane\.alpha\.kubernetes\.io/leader}'

kube-controller-manager

To find the kube-controller-manager leader using kubectl:

kubectl -n kube-system get endpoints kube-controller-manager -o jsonpath='{.metadata.annotations.control-plane\.alpha\.kubernetes\.io/leader}'