I have created these files ca.cert and kubelet.service (systemd file with apiserver's IP and options). How can I simply add this new node to the cluster?
To do this in the latest version (tested on 1.12) you can issue following command on the master node:
kubeadm token create --print-join-commandIt will then print out a new join command (like the one you got after kubeadmn init):
kubeadm join 192.168.1.101:6443 --token tokentoken.lalalalaqyd3kavez --discovery-token-ca-cert-hash sha256:complexshaoverhereNow run the above command on worker node, it must have docker, kubelet and kubeadm installed. You will be able to join the worker node.
Refer this official document here for more details.