kubectl describe pods で見ると下記のエラーが出ている

  Warning  FailedCreatePodSandBox  90s               kubelet            Failed to create pod sandbox: rpc error: code = Unknown desc = failed to setup network for sandbox "49a5d016c6aacfbea51d08b00f0edef8575396ba4843294ee176269bdc2d4132": failed to delegate add: failed to set bridge addr: "cni0" already has an IP address different from 10.244.6.1/24

Nodeを1度再起動してあげれば治る

Unable to connect to the server: x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "kubernetes")

下記実行

mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config
unset KUBECONFIG
export KUBECONFIG=/etc/kubernetes/admin.conf