Can somebody elaborate what is the use of configmap signing which is given here in kubernetes doc .
It's used in TLS bootstrapping a kubelet in kubeadm. When you run kubeadm join command the API server returns the ConfigMap with the kubeconfig contents as normal. Extra data items on that ConfigMap contains JWS signatures. Kubeadm finds the correct signature based on the token-id part of the token.Kubeadm verifies the JWS and can now trust the server. Further communication is simpler as the CA certificate in the kubeconfig file can be trusted