There is a k8s single master node, I need to back it up and restore it I googled this topic and found a solution - https://elastisys.com/2018/12/10/backup-kubernetes-how-and-why/
Everything looked easy; so,I followed the instruction and got a copy of the certificates and a snapshot of the etcd database.
But at last, I am not able to find kubeadm-config.yaml on my master server.
Where to find this file?