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Proper way of Kubeadm reset 



Login to the Master Node:




#####################

sudo kubeadm reset



sudo systemctl stop docker && sudo systemctl stop kubelet



sudo rm -rf /etc/kubernetes/



sudo rm -rf .kube/



sudo rm -rf /var/lib/kubelet/



sudo rm -rf /var/lib/cni/



sudo rm -rf /etc/cni/





sudo rm -rf /var/lib/etcd/



ifconfig cni0 down

ifconfig flannel.1 down

ifconfig docker0 down



sudo ip link delete cni0

sudo ip link delete flannel.1



kubeadm reset does not delete any of the iptables rules it originally created. In other words, if you try to bootstrap your cluster with a different pod networking CIDR range or different networking options, you might run into trouble.





Please note if you are using a firewall configuration tool like ufw, which uses iptables as system-of-record, the commands below might render your system inaccessible.





Because of this, we recommend that you flush all iptables rules:



iptables -F && iptables -t nat -F && iptables -t mangle -F && iptables -X



after you run kubeadm reset and before you re-bootstrap the node (kubeadm init) with new parameters.



This ensures that you really have a blank slate, and potentially saves you a lot of nasty network debugging.



sudo systemctl start docker && sudo systemctl start kubelet




sudo kubeadm init --pod-network-cidr=10.244.0.0/16 --control-plane-endpoint=<Specify a stable IP address or DNS name for the control plane >


# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/2140ac876ef134e0ed5af15c65e414cf26827915/Documentation/kube-flannel.yml

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