我的k8s是1.9版本的
安装网络插件时我用如下命令：

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/v0.9.1/Documentation/kube-flannel.yml

报错

Warning: rbac.authorization.k8s.io/v1beta1 ClusterRole is deprecated in v1.17+, unavailable in v1.22+; use rbac.authorization.k8s.io/v1 ClusterRole
clusterrole.rbac.authorization.k8s.io/flannel created
Warning: rbac.authorization.k8s.io/v1beta1 ClusterRoleBinding is deprecated in v1.17+, unavailable in v1.22+; use rbac.authorization.k8s.io/v1 ClusterRoleBinding
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
error: unable to recognize "https://raw.githubusercontent.com/coreos/flannel/v0.9.1/Documentation/kube-flannel.yml": no matches for kind "DaemonSet" in version "extensions/v1beta1"

看意思应该是这个网络插件的地址不适合1.9版本的k8s，于是换一个地址如下：

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

就ok了