The script reports "OK" even if a node is down, if docker is down or if the Kubelet has crashed or entered an error condition.
In this case, I stopped the Kubelet on docker02, but the script says the node is OK.
$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
docker01 Ready controlplane,etcd,worker 421d v1.17.4
docker02 NotReady controlplane,etcd,worker 421d v1.17.4
docker03 Ready controlplane,etcd,worker 421d v1.17.4
$ ./check_kube_nodes.sh -k kube_config_cluster.yml
OK - Kubernetes nodes all OK
$
The script reports "OK" even if a node is down, if docker is down or if the Kubelet has crashed or entered an error condition.
In this case, I stopped the Kubelet on docker02, but the script says the node is OK.