k8s（kubernetes）服务部署dashboard时出现ImagePullBackOff/CrashLoopBackOff解决办法

部署服务时镜像拉取过程当中出现:ImagePullBackOff
kubectl describe pods kubernetes-dashboard-975499656-krwl7 -n kube-system
查看pod的详细状况

Events:
  Type     Reason     Age                    From                Message
  ----     ------     ----                   ----                -------
  Normal   Scheduled  4m38s                  default-scheduler   Successfully assigned kube-system/kubernetes-dashboard-975499656-krwl7 to k8s-node2
  Normal   Pulling    2m32s (x4 over 4m38s)  kubelet, k8s-node2  Pulling image "k8s.gcr.io/kubernetes-dashboard-amd64:v1.10.1"
  Warning  Failed     2m16s (x4 over 4m22s)  kubelet, k8s-node2  Failed to pull image "k8s.gcr.io/kubernetes-dashboard-amd64:v1.10.1": rpc error: code = Unknown desc = Error response from daemon: Get https://k8s.gcr.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)
  Warning  Failed     2m16s (x4 over 4m22s)  kubelet, k8s-node2  Error: ErrImagePull
  Normal   BackOff    112s (x6 over 4m22s)   kubelet, k8s-node2  Back-off pulling image "k8s.gcr.io/kubernetes-dashboard-amd64:v1.10.1"
  Warning  Failed     99s (x7 over 4m22s)    kubelet, k8s-node2  Error: ImagePullBackOff

分析：这个拉取的国外的镜像源，是有点慢，网络很差的时候常常会出现这种状况，能够提早把须要的镜像下载好
解决办法:
更换国内镜像源，搜索须要下载的镜像
①编辑文件 /etc/docker/daemon.json 加入"registry-mirrors":["https://docker.mirrors.ustc.edu.cn"]

重载配置文件重启docker生效

systemctl daemon-reload 
systemctl restart docker

②搜索须要的镜像，如:k8s.gcr.io/kubernetes-dashboard-amd64:v1.10.1

③拉取指定镜像

④tag为配置文件中须要的镜像名k8s.gcr.io/kubernetes-dashboard-amd64:v1.10.1

docker tag loveone/kubernetes-dashboard-amd64:v1.10.1 k8s.gcr.io/kubernetes-dashboard-amd64:v1.10.1

完成后再试一次(注意最好每一个节点都作这样的操做，由于调度器随机选择节点部署，简而言之是在被部署的节点上操做)
从新部署
①kubectl delete -f kubernetes-dashboard.yaml,
②kubectl apply -f kubernetes-dashboard.yaml 或者 kubectl create -f kubernetes-dashboard.yaml --save-config
出现以下报错

kubectl logs kubernetes-dashboard-975499656-xlx5b -n kube-system

• 查看pod日志以下
  Error from server: Get https://192.168.40.131:10250/containerLogs/kube-system/kubernetes-dashboard-975499656-xlx5b/kubernetes-dashboard: dial tcp 192.168.40.131:10250: connect: no route to host
  
• 分析:因而可知，部署服务时访问节点131的10250端口链接被拒绝，推测多是防火墙的缘由
• 解决办法:
  ①查看服务端口是否被占用，!是否已经启起来了；
  能够看到，端口启动正常；
  ②telnet测试一下端口（我这里是master机器上测试的）
  
  果真不通
  ③查看节点1的防火墙状态
  果真是防火墙的缘由
  
  
  
  再试端口就通了
  
  从新部署试试
  成功