invalid or incomplete external CA: failure loading key for apiserver: couldn't load the private key file /etc/kubernetes/pki/apiserver.key: open /etc/kubernetes/pki/apiserver.key: no such file or directory To see the stack trace of this error execute with --v=5 or higher

Question: invalid or incomplete external CA: failure loading key for apiserver: couldn't load the private key file /etc/kubernetes/pki/apiserver.key: open /etc/kubernetes/pki/apiserver.key: no such file or directory
To see the stack trace of this error execute with --v=5 or higher

Login to See the Rest of the Answer

Answer: Do you know someone who can answer this question? This happens when you do 
sudo kubeadm init --pod-network-cidr=10.244.0.0/16 on the node (not master node) but other nodes joining the cluser. The Error is shown above.