When I run kubeadm::init command, all pods are running except coredns pods. when I describe the pods, its showing something cni initialization failed. do I need any network plugin to be installed before running kubeadm::init??
No, the network add-on is only added after kubeadm init, the documentation is explicit on this topic: https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/#pod-network