Kubernetes failed to setup network for pod after executed kubeadm reset

Question

I initialized Kubernetes with kubeadm init, and after I used kubeadm reset to reset it I found --pod-network-cidr was wrong. After correct

Answer 1

I had an issue after change of --pod-network-cidr, with join reporting success but no node being added. kubeadm reset and re-join had no effect. Solved through apt-get remove kubelet kubeadm kubectl kubernetes-cni after reset, followed by docker and/or machine restart, followed by reinstall and then join agin.

Answer 2

This document helped a lot:

https://github.com/feiskyer/kubernetes-handbook/blob/master/en/troubleshooting/pod.md

specially the part which applies to this issue:

$ ip link set cni0 down
$ brctl delbr cni0  

If you do this on the api servers and then just reboot the machine it should stabilize pretty quickly.

Answer 3

I figured it out, if you change --pod-network-cidr when you reinitialize kubernetes via kubeadm init, you should delete some auto-created things, just follow the steps below before you execute kubeadm init again:

1. execute kubeadm reset on master and nodes.

2. execute etcdctl rm --recursive registry reset data in etcd.

3. rm -rf /var/lib/cni on master and nodes

4. rm -rf /run/flannel on master and nodes

5. rm -rf /etc/cni on master and nodes

6. ifconfig cni0 down on master and nodes

7. brctl delbr cni0 on master and nodes

Now, my Kubernetes works fine :)

Answer 4

What helped for me:

• ip link set cni0 down

  brctl delbr cni0

  Delete and re-apply flannel

So no need to build up your cluster again

Answer 5

I had a similar issue and the fix in that case was to apply the flannel pod network to the cluster:

wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
kubectl apply -f kube-flannel.yml

Answer 6

After kubeadm reset and before kubeadm init do the following on master and worker nodes:

1. kubeadm reset
2. systemctl stop kubelet & systemctl stop docker
3. rm -rf /var/lib/cni/
4. rm -rf /var/lib/kubelet/*
5. rm -rf /etc/cni/
6. ifconfig cni0 down & ip link delete cni0
7. ifconfig flannel.1 down & ip link delete flannel.1
8. ifconfig docker0 down

Tested with kubernetes server version: v1.13.2 & flannel: v0.10.0-amd64

github issue reference