Centos7 安装k8s
按照步骤失败后就用kubeadm reset命令重置，后来就好了
重置Kubernetes
https://www.jianshu.com/p/31f7dda9ccf7
重置命令
sudo kubeadm reset
结果：
W0419 09:34:58.549504 4085 removeetcdmember.go:61] [reset] failed to remove etcd member: etcdserver: re-configuration failed due to not enough started members
.Please manually remove this etcd member using etcdctl
[reset] Stopping the kubelet service
[reset] Unmounting mounted directories in "/var/lib/kubelet"
[reset] Deleting contents of config directories: [/etc/kubernetes/manifests /etc/kubernetes/pki]
[reset] Deleting files: [/etc/kubernetes/admin.conf /etc/kubernetes/kubelet.conf /etc/kubernetes/bootstrap-kubelet.conf /etc/kubernetes/controller-manager.conf /etc/kubernetes/scheduler.conf]
[reset] Deleting contents of stateful directories: [/var/lib/etcd /var/lib/kubelet /var/lib/dockershim /var/run/kubernetes /var/lib/cni]
The reset process does not clean CNI configuration. To do so, you must remove /etc/cni/net.d
The reset process does not reset or clean up iptables rules or IPVS tables.
If you wish to reset iptables, you must do so manually by using the "iptables" command.
If your cluster was setup to utilize IPVS, run ipvsadm --clear (or similar)
to reset your system's IPVS tables.
The reset process does not clean your kubeconfig files and you must remove them manually.
Please, check the contents of the $HOME/.kube/config file.
手工清除：
删除net.d
rm -rf /etc/cni/net.d
重置iptables
iptables -F && iptables -t nat -F && iptables -t mangle -F && iptables -X
sysctl net.bridge.bridge-nf-call-iptables=1
手动执行以下命令来清除对应的残余网卡信息：
sudo ip link del cni0
sudo ip link del flannel.1
删除 $HOME/.kube/config
rm -rf $HOME/.kube/config
