错误一：coredns的状态是pending

原因1：master上的flannel镜像拉取失败，导致获取不到解析的IP
解决方法：

[root@master ~]# kubectl delete -f kube-flannel.yml    #先删除安装的CNI插件
[root@master ~]# docker load --input flannel-0.11.0-amd64.tar #导入镜像
[root@master ~]# kubectl apply -f kube-flannel.yml  #再次安装
[root@master ~]# kubectl get pods -n kube-system -o wide

原因2：没有本地解析，所以coredns才是pending

[root@master ~]# cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

解决方法：本地解析

[root@master ~]# cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.13.141 master
192.168.13.142 node1
192.168.13.143 node2

错误二：集群测试pod状态pending

[root@master ~]# kubectl get pods -n kube-system -o wide 查看状态

原因：发现两个node节点上的flannel镜像自动拉取失败
解决方法：我们需要去手动导入镜像

[root@node1 ~]# docker load --input flannel-0.11.0-amd64.tar
7bff100f35cb: Loading layer [==================================================>]  4.672MB/4.672MB
5d3f68f6da8f: Loading layer [==================================================>]  9.526MB/9.526MB
9b48060f404d: Loading layer [==================================================>]  5.912MB/5.912MB
3f3a4ce2b719: Loading layer [==================================================>]  35.25MB/35.25MB
9ce0bb155166: Loading layer [==================================================>]   5.12kB/5.12kB
Loaded image: quay.io/coreos/flannel:v0.11.0-amd64
[root@node2 ~]# docker load --input flannel-0.11.0-amd64.tar
7bff100f35cb: Loading layer [==================================================>]  4.672MB/4.672MB
5d3f68f6da8f: Loading layer [==================================================>]  9.526MB/9.526MB
9b48060f404d: Loading layer [==================================================>]  5.912MB/5.912MB
3f3a4ce2b719: Loading layer [==================================================>]  35.25MB/35.25MB
9ce0bb155166: Loading layer [==================================================>]   5.12kB/5.12kB
Loaded image: quay.io/coreos/flannel:v0.11.0-amd64

然后删除pod重新进行集群测试
[root@master ~]# kubectl get deployment   
NAME    READY   UP-TO-DATE   AVAILABLE   AGE
nginx   0/1     1            0           16m
[root@master ~]# kubectl delete deployment nginx  #删除
deployment.extensions "nginx" deleted
[root@master ~]# kubectl get pods -n kube-system -o wide
NAME                             READY   STATUS    RESTARTS   AGE   IP               NODE     NOMINATED NODE   READINESS GATES
coredns-8686dcc4fd-p56rf         1/1     Running   0          36m   10.244.0.3       master   <none>           <none>
coredns-8686dcc4fd-qnhjv         1/1     Running   0          36m   10.244.0.2       master   <none>           <none>
etcd-master                      1/1     Running   0          35m   192.168.13.141   master   <none>           <none>
kube-apiserver-master            1/1     Running   0          35m   192.168.13.141   master   <none>           <none>
kube-controller-manager-master   1/1     Running   0          35m   192.168.13.141   master   <none>           <none>
kube-flannel-ds-amd64-j9mlk      1/1     Running   0          25m   192.168.13.141   master   <none>           <none>
kube-flannel-ds-amd64-p89mh      1/1     Running   0          19m   192.168.13.143   node2    <none>           <none>
kube-flannel-ds-amd64-rsln6      1/1     Running   0          19m   192.168.13.142   node1    <none>           <none>
kube-proxy-2pfmm                 1/1     Running   0          36m   192.168.13.141   master   <none>           <none>
kube-proxy-tmd2c                 1/1     Running   0          19m   192.168.13.142   node1    <none>           <none>
kube-proxy-tvn54                 1/1     Running   0          19m   192.168.13.143   node2    <none>           <none>
kube-scheduler-master            1/1     Running   0          35m   192.168.13.141   master   <none>           <none>

[root@master ~]# kubectl get pod,svc
NAME                         READY   STATUS    RESTARTS   AGE
pod/nginx-5f965696dd-2wcfn   1/1     Running   0          2m52s

NAME                 TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.1.0.1      <none>        443/TCP        39m
service/nginx        NodePort    10.1.113.89   <none>        80:32439/TCP   21m
此时pod状态就是Running了

[root@master ~]# curl 192.168.13.142:32439   #访问页面也是能成功
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>