Node unable to join cluster - saying token expired

Question

I have executed the kubeadm init command on my master and now I'm trying to execute the node join command on my node but I encountered the following error:

[discovery] Failed to connect to API Server "<master_addr>:6443": token id "higwl" is invalid for this cluster or it has expired. Use "kubeadm token create" on the master node to creating a new valid token

What do I do?

Answer 1

Hey @Ashish, seems like the token has expired. As mentioned in the error log try to create the token for master again, use the following commands:

# login to master node
# create a new bootstrap token
$ kubeadm token create
abcdef.1234--------

# get root ca cert fingerprint
$ openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | openssl dgst -sha256 -hex | sed 's/^.* //'
e18105ef24bacebb23d694dad491e8ef1c2ea9ade944e784b1f03a15a0d5ecea 

# login to the new worker node
# join to cluster 
$ kubeadm join --token abcdef.1234567890abcdef --discovery-token-ca-cert-hash sha256:e18105ef24bacebb23d694dad491e8ef1c2ea9ade944e784b1f03a15a0d5ecea 1.2.3.4:6443

Answer 2

@Eric's answer is on point. There's another way of doing this.

Ever heard of Discovery files? So basically discovery files provide a very trusted out-of-bound connection between the master and the bootstrapping nodes. Use the join command like this after creating a new token for the master.

kubeadm join --token abcdef.1234567890abcdef --discovery-file a.conf