Kube Node Unreachable

KubeNodeUnreachable #

Meaning #

Kubernetes node is unreachable and some workloads may be rescheduled.

Impact #

The performance of the cluster deployments is affected, depending on the overall workload and the type of the node.

Diagnosis #

The notification details should list the node that’s not reachable. For Example:

 - alertname = KubeNodeUnreachable
 - node = node1.example.com

Login to the cluster. Check the status of that node:

$ kubectl get node $NODE -o yaml

The output should describe why the node is not reachable.

Common failure scenarios:

  • disruptive software upgrades
  • network patitioning due to hardware failures
  • firewall rules
  • virtual machines suspended due to storage area network problems
  • system crashes / freezes due to software or hardware malfunctions

Mitigation #

In case of maintenance ensure to cordon and drain node.

In other cases ensure storage and networking redundancy if applicable.

See KubeNode See node problem detector See Watchdog timer