k3s-agent not starting on ec2 error "failed to get CA certs" about k3s

[brandond]

Make sure that you have opened the correct ports between your nodes, ref: https://docs.k3s.io/installation/requirements#inbound-rules-for-k3s-nodes

If the server and agent are not on the same private network, and the agent cannot connect to the server by it's private IP, ensure that you're properly setting the --node-external-ip on the server, to an address that is reachable by the agent. Also ensure that the agent and server are both able to connect to the server by that address.

[rd-raven]

@brandond both server and agent are in the same subnet in same VPC however, API Server port 6443 is open but Kubelet Metrics port 10250 is not but strangely enough after when I didn't see any solution and shutdown and came back next day and turn the instances on again, both the server and the agent were up and deployments made on server were perfectly being scheduled on agent, what I found is that in above scenario if we just restart (did another experiment to prove it) both server and agent connect successfully, thanks for pointing out the ports I'll keep at-least metrics port also open next time, still my issue is resolved so thanks again !!