kubernetes入門實踐

時間  2019-11-18
標籤 kubernetes 入門 實踐 简体版
原文   原文鏈接

k8s中文文檔

  • k8s概念比較多，有什麼概念的疑惑的推薦看k8s中文文檔。

me的環境

  • 操做系統：centos7
  • docker：1.12.6

環境跟me的不一致？不要慌，基本大部分操做都是行的通的。node

還慌？那就直接用網頁在線版的kubernets吧mysql

kubernets單機版安裝部署

kubernetes部署算是有必定門檻的。爲了避免從入門到放棄，推薦一開始安裝單機版做爲入門熟悉kubectl指令、瞭解工做原理。linux

安裝流程，切換成root

 
 
 
  # 關閉centos自帶的防火牆 

 

  
  
  

 

  
  $ sudo systemctl disable firewalld 

 

  
  
  

 

  
  $ sudo systemctl stop firewalld 

 

  
  
  

 
 
 
  # 安裝etcd和kubernetes軟件（會自動安裝docker） 

 

  
  
  

 

  
  $ sudo yum install -y etcd kubernetes

修改兩處配置

  • Docker配置文件/etc/sysconfig/docker, OPTIONS=’–selinux-enabled=false –insecure-registry gcr.io’
 
 
 
  # Modify these options if you want to change the way the docker daemon runs 

 

  
  
  

 
 
 
  OPTIONS='--selinux-enabled=false 
 
  --insecure-registry 
 
  gcr.io' 

 

  
  
  

 
 
 
  if 
 
  [ 
 
  -z 
 
  "${DOCKER_CERT_PATH}" 
 
  ]; 
 
  then 

 

  
  
  

 
 
 
  DOCKER_CERT_PATH=/etc/docker 

 

  
  
  

 
 
 
  fi 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # Do not add registries in this file anymore. Use /etc/containers/registries.conf 

 

  
  
  

 
 
 
  # from the atomic-registries package. 

 

  
  
  

 
 
 
  # 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # docker-latest daemon can be used by starting the docker-latest unitfile. 

 

  
  
  

 
 
 
  # To use docker-latest client, uncomment below lines 

 

  
  
  

 
 
 
  #DOCKERBINARY=/usr/bin/docker-latest 

 

  
  
  

 
 
 
  #DOCKERDBINARY=/usr/bin/dockerd-latest 

 

  
  
  

 
 
 
  #DOCKER_CONTAINERD_BINARY=/usr/bin/docker-containerd-latest 

 

  
  
  

 
 
 
  #DOCKER_CONTAINERD_SHIM_BINARY=/usr/bin/docker-containerd-shim-latest
  • Kubernetes apiservce配置文件/etc/kubernetes/apiserver,把–admission_control參數鐘的ServiceAccount刪除
 
 
 
  ### 

 

  
  
  

 
 
 
  # kubernetes system config 

 

  
  
  

 
 
 
  # 

 

  
  
  

 
 
 
  # The following values are used to configure the kube-apiserver 

 

  
  
  

 
 
 
  # 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # The address on the local server to listen to. 

 

  
  
  

 
 
 
  KUBE_API_ADDRESS="--insecure-bind-address=0.0.0.0" 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # The port on the local server to listen on. 

 

  
  
  

 
 
 
  # KUBE_API_PORT="--port=8080" 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # Port minions listen on 

 

  
  
  

 
 
 
  # KUBELET_PORT="--kubelet-port=10250" 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # Comma separated list of nodes in the etcd cluster 

 

  
  
  

 
 
 
  KUBE_ETCD_SERVERS="--etcd-servers=http://127.0.0.1:2379" 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # Address range to use for services 

 

  
  
  

 
 
 
  KUBE_SERVICE_ADDRESSES="--service-cluster-ip-range=10.254.0.0/16" 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # default admission control policies 

 

  
  
  

 
 
 
  KUBE_ADMISSION_CONTROL="--admission-control=NamespaceLifecycle,NamespaceExists,LimitRanger,SecurityContextDeny,ResourceQuota" 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # Add your own! 

 

  
  
  

 
 
 
  KUBE_API_ARGS=""

啓動全部服務

 
 
 
  # systemctl start etcd 

 

  
  
  

 
 
 
  # systemctl start docker 

 

  
  
  

 
 
 
  # systemctl start kube-apiserver 

 

  
  
  

 
 
 
  # systemctl start kube-controller-manager 

 

  
  
  

 
 
 
  # systemctl start kube-scheduler 

 

  
  
  

 
 
 
  # systemctl start kubelet 

 

  
  
  

 
 
 
  # systemctl start kube-proxy

初入門小實例

  • 部署nginx服務nginx

       
    
    
  $ kubectl run my-nginx --image=nginx --port= 
 
    80 

   
    
    
    
    

   
    
    
  $ kubectl get pod 
 
    # 查看pod

發現pod狀態不管多久都是處於pending。READY字段一直是0/1,服務部署失敗的緣由是」中國牆「的問題致使沒法下載pod啓動時須要的谷歌鏡像，因此咱們得間接的建立所需的鏡像。git

補充： Pending狀態表示API Server已經建立Pod，但Pod內還有一個或者多個容器沒有建立，或者正在下載鏡像的過程。詳細的參考Pod聲明週期和重啓策略github

  • 建立gcr.io/google_containers/pause-amd64:3.0鏡像sql

       
    
    
  $ docker pull googlecontainer/pause-amd64: 
 
    3.0 

   
    
    
    
    

   
    
    
  $ docker tag googlecontainer/pause-amd64: 
 
    3.0 gcr.io/google_containers/pause-amd64: 
 
    3.0

    ​

kubernets指令

  • 實例流程
 
 
 
  # 查看版本 

 

  
  
  

 

  
  $ kubectl version 

 

  
  
  

 

  
  Client Version: version.Info{Major: 
 
  "1", Minor: 
 
  "5", GitVersion: 
 
  "v1.5.2", GitCommit: 
 
  "269f928217957e7126dc87e6adfa82242bfe5b1e", GitTreeState: 
 
  "clean", BuildDate: 
 
  "2017-07-03T15:31:10Z", GoVersion: 
 
  "go1.7.4", Compiler: 
 
  "gc", Platform: 
 
  "linux/amd64"} 

 

  
  
  

 

  
  Server Version: version.Info{Major: 
 
  "1", Minor: 
 
  "5", GitVersion: 
 
  "v1.5.2", GitCommit: 
 
  "269f928217957e7126dc87e6adfa82242bfe5b1e", GitTreeState: 
 
  "clean", BuildDate: 
 
  "2017-07-03T15:31:10Z", GoVersion: 
 
  "go1.7.4", Compiler: 
 
  "gc", Platform: 
 
  "linux/amd64"} 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # 顯示集羣信息 

 

  
  
  

 

  
  $ kubectl cluster-info 

 

  
  
  

 

  
  Kubernetes master is running at http://localhost: 
 
  8080 

 

  
  
  

 

  
  To further debug and diagnose cluster problems, use 
 
  'kubectl cluster-info dump'. 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # 查看集羣中有幾個Node 

 

  
  
  

 

  
  $ kubectl get nodes 

 

  
  
  

 

  
  NAME STATUS AGE 

 

  
  
  

 
 
 
  127.0. 
 
  0.1 Ready 
 
  18h 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # 運行一個鏡像 

 

  
  
  

 

  
  $ kubectl run my-nginx --image=nginx --replicas= 
 
  2 --port= 
 
  80 

 

  
  
  

 

  
  deployment 
 
  "my-nginx" created 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # 查看pod 

 

  
  
  

 

  
  $ kubectl get pods 

 

  
  
  

 

  
  NAME READY STATUS RESTARTS AGE 

 

  
  
  

 

  
  my-nginx- 
 
  379829228-cwlbb 
 
  0/ 
 
  1 ContainerCreating 
 
  0 
 
  20s 

 

  
  
  

 

  
  my-nginx- 
 
  379829228-czk6w 
 
  1/ 
 
  1 Running 
 
  0 
 
  20s 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # 查看服務詳情信息 

 

  
  
  

 

  
  $ kubectl describe pod my-nginx- 
 
  379829228-cwlbb 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # 查看已部署 

 

  
  
  

 

  
  $ kubectl get deployments 

 

  
  
  

 

  
  NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE 

 

  
  
  

 

  
  my-nginx 
 
  2 
 
  2 
 
  2 
 
  2 
 
  3m 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # 刪除pod 

 

  
  
  

 

  
  $ kubectl delete pod my-nginx- 
 
  379829228-cwlbb 

 

  
  
  

 

  
  pod 
 
  "my-nginx-379829228-cwlbb" deleted 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # 再次查看pod，發現因爲replicas機制，pod又生成一個新的 

 

  
  
  

 

  
  $ kubectl get pods 

 

  
  
  

 

  
  NAME READY STATUS RESTARTS AGE 

 

  
  
  

 

  
  my-nginx- 
 
  379829228-czk6w 
 
  1/ 
 
  1 Running 
 
  0 
 
  11m 

 

  
  
  

 

  
  my-nginx- 
 
  379829228-gjd7d 
 
  0/ 
 
  1 ContainerCreating 
 
  0 
 
  5s 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # 刪除部署的my-nginx服務。完全刪除pod 

 

  
  
  

 

  
  $ kubectl delete deployment my-nginx 

 

  
  
  

 

  
  deployment 
 
  "my-nginx" deleted

對比docker命令

k8s的學習路線基本都是從docker[容器]到k8s的，所以兩個對比理解有助於記憶docker

 
 
 
  # docker run 

 

  
  
  

 

  
  $ docker run -d -e DOMAIN=cluster --name my-nginx -p 
 
  80: 
 
  80 nginx 

 

  
  
  

 

  
  $ kubectl run my-nginx --image=nginx --port= 
 
  80 --env= 
 
  "DOMAIN=cluster" 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # docker ps  

 

  
  
  

 

  
  $ docker ps 

 

  
  
  

 

  
  $ kubectl get pods 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # docker exec 

 

  
  
  

 

  
  $ docker exec [容器id] ls 

 

  
  
  

 

  
  $ kubectl exec [pod_id] ls 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # docker exec 交互式 

 

  
  
  

 

  
  $ docker exec -it [容器id] /bin/sh 

 

  
  
  

 

  
  $ kubectl exec -it [pod_id] -- /bin/sh 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # docker info 

 

  
  
  

 

  
  $ docker info 

 

  
  
  

 

  
  $ kubectl cluster-info

重要名詞

名詞 翻譯
Namespace 命名空間
Endpoint 服務端點
Controller Manager 管理控制中心
Replication 副本控制器

yaml文件管理服務

  • 用yaml文件來建立服務shell

       
     

   
    
    
    
    

   
     
 
    # vi nginx.yaml 

   
    
    
    
    

   
     

   
    
    
    
    

   
     
 
    piVersion: 
 
    extensions/v1beta1 

   
    
    
    
    

   
     
 
    kind: 
 
    Deployment 

   
    
    
    
    

   
     
 
    metadata: 

   
    
    
    
    

   
     
 
    name: 
 
    my-nginx 

   
    
    
    
    

   
     
 
    spec: 

   
    
    
    
    

   
     
 
    replicas: 
 
    3 

   
    
    
    
    

   
     
 
    template: 

   
    
    
    
    

   
     
 
     metadata: 

   
    
    
    
    

   
     
 
     labels: 

   
    
    
    
    

   
     
 
     app: 
 
    nginx 

   
    
    
    
    

   
     
 
     spec: 

   
    
    
    
    

   
     
 
     containers: 

   
    
    
    
    

   
     
 
     - name: 
 
    nginx 

   
    
    
    
    

   
     
 
     image: 
 
    nginx:1.7.9 

   
    
    
    
    

   
     
 
     ports: 

   
    
    
    
    

   
     
 
     - containerPort: 
 
    80

  • 啓動管理服務centos

       
     

   
    
    
    
    

   
     
 
    # 根據yaml文件建立服務 

   
    
    
    
    

   
     

   
    
    
    
    

   
    
    
  $ kubectl create -f nginx.yaml 

   
    
    
    
    

   
    
    
  deployment 
 
    "my-nginx" created 

   
    
    
    
    

   
     

   
    
    
    
    

   
     
 
    # 查看deployment 

   
    
    
    
    

   
     

   
    
    
    
    

   
    
    
  $ kubectl get deployments 

   
    
    
    
    

   
    
    
  NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE 

   
    
    
    
    

   
    
    
  my-nginx 
 
    3 
 
    3 
 
    3 
 
    3 
 
    6s 

   
    
    
    
    

   
     

   
    
    
    
    

   
     
 
    # 查看Pod 

   
    
    
    
    

   
     

   
    
    
    
    

   
    
    
  $ kubectl get pod 

   
    
    
    
    

   
    
    
  NAME READY STATUS RESTARTS AGE 

   
    
    
    
    

   
    
    
  my-nginx- 
 
    4087004473-dtrjp 
 
    1/ 
 
    1 Running 
 
    0 
 
    7s 

   
    
    
    
    

   
    
    
  my-nginx- 
 
    4087004473-jz80p 
 
    1/ 
 
    1 Running 
 
    0 
 
    7s 

   
    
    
    
    

   
    
    
  my-nginx- 
 
    4087004473-wh576 
 
    1/ 
 
    1 Running 
 
    0 
 
    7s 

   
    
    
    
    

   
     

   
    
    
    
    

   
     
 
    # 根據yaml文件刪除服務 

   
    
    
    
    

   
     

   
    
    
    
    

   
    
    
  $ kubectl delete -f nginx.yaml 

   
    
    
    
    

   
    
    
  deployment 
 
    "my-nginx" deleted 

   
    
    
    
    

   
     

   
    
    
    
    

   
    
    
  $ kubectl get pod 

   
    
    
    
    

   
    
    
  No resources found. 

   
    
    
    
    

   
    
    
  $ kubectl get deployment 

   
    
    
    
    

   
    
    
  No resources found.

    ​

    ​

Service

  • 到此，咱們部署一個nginx服務

       
    
    
  $ kubectl run my-nginx --image=nginx --port= 
 
    80 

   
    
    
    
    

   
     

   
    
    
    
    

   
     
 
    # 建立一個service 且將其暴露到集羣外可供訪問 

   
    
    
    
    

   
     

   
    
    
    
    

   
    
    
  $ kubectl expose deployment/my-nginx --type= 
 
    "NodePort" --port 
 
    80 

   
    
    
    
    

   
    
    
  service 
 
    "my-nginx" exposed 

   
    
    
    
    

   
     

   
    
    
    
    

   
     
 
    # 此時service列表多個my-nginx服務 

   
    
    
    
    

   
     

   
    
    
    
    

   
    
    
  $ kubectl get services 

   
    
    
    
    

   
    
    
  NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE 

   
    
    
    
    

   
    
    
  kubernetes 
 
    10.254. 
 
    0.1 <none> 
 
    443/TCP 
 
    7d 

   
    
    
    
    

   
    
    
  my-nginx 
 
    10.254. 
 
    255.103 <nodes> 
 
    80: 
 
    32589/TCP 
 
    7s

宿主主機內訪問該服務

 

  
  $ kubectl describe service/my-nginx 

 

  
  
  

 
 
 
  # 顯示的字段有Endpoints: 172.17.0.2:80 

 

  
  
  

 

  
  $ curl 
 
  172.17. 
 
  0.2. 
 
  80

Alt text

同網段的機器訪問該服務

 

  
  $ curl 
 
  192.168. 
 
  33.101: 
 
  32589

deployments

 
 
 
  # 運行nginx鏡像 

 

  
  
  

 

  
  $ kubectl run my-nginx --image=nginx --port= 
 
  80 

 

  
  
  

 
 
 
  # 交互式 shell 的方式運行 pod 

 

  
  
  

 

  
  $ kubectl run -i --tty my-nginx --image=nginx --port= 
 
  80 -- sh 

 

  
  
  

 
 
 
  # 連接到運行中的容器 

 

  
  
  

 

  
  $ kubectl attach my-nginx- 
 
  532658988- 
 
  10kxd -i 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # 查看deployment 

 

  
  
  

 

  
  $ kubectl get deployments 

 

  
  
  

 

  
  NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE 

 

  
  
  

 

  
  my-nginx 
 
  1 
 
  1 
 
  1 
 
  1 
 
  25m 

 

  
  
  

 
 
 
  # 擴展10個副本 

 

  
  
  

 

  
  $ kubectl scale deployment my-nginx --replicas= 
 
  10 

 

  
  
  

 

  
  deployment 
 
  "my-nginx" scaled 

 

  
  
  

 

  
  $ kubectl scale deployment/my-nginx --replicas= 
 
  10 
 
  # 做用效果等同上一條命令  

 

  
  
  

 

  
  deployment 
 
  "my-nginx" scaled 

 

  
  
  

 
 
 
  # 再次顯示deployment 

 

  
  
  

 

  
  $ kubectl get deployments 

 

  
  
  

 

  
  NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE 

 

  
  
  

 

  
  my-nginx 
 
  10 
 
  10 
 
  10 
 
  1 
 
  26m 

 

  
  
  

 

  
  $ kubectl get pods 

 

  
  
  

 

  
  NAME READY STATUS RESTARTS AGE 

 

  
  
  

 

  
  my-nginx- 
 
  379829228- 
 
  38hkg 
 
  1/ 
 
  1 Running 
 
  0 
 
  5m 

 

  
  
  

 

  
  my-nginx- 
 
  379829228- 
 
  7j15l 
 
  1/ 
 
  1 Running 
 
  0 
 
  31m 

 

  
  
  

 

  
  my-nginx- 
 
  379829228-c8mt3 
 
  1/ 
 
  1 Running 
 
  0 
 
  5m 

 

  
  
  

 

  
  my-nginx- 
 
  379829228-f6mm8 
 
  1/ 
 
  1 Running 
 
  0 
 
  5m 

 

  
  
  

 

  
  my-nginx- 
 
  379829228-q1rj0 
 
  1/ 
 
  1 Running 
 
  0 
 
  5m 

 

  
  
  

 

  
  my-nginx- 
 
  379829228-qg7lf 
 
  1/ 
 
  1 Running 
 
  0 
 
  5m 

 

  
  
  

 

  
  my-nginx- 
 
  379829228-rjfbq 
 
  1/ 
 
  1 Running 
 
  0 
 
  5m 

 

  
  
  

 

  
  my-nginx- 
 
  379829228-v581r 
 
  1/ 
 
  1 Running 
 
  0 
 
  5m 

 

  
  
  

 

  
  my-nginx- 
 
  379829228-wh49w 
 
  1/ 
 
  1 Running 
 
  0 
 
  5m 

 

  
  
  

 

  
  my-nginx- 
 
  379829228-wpn98 
 
  1/ 
 
  1 Running 
 
  0 
 
  5m 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # 縮擴到1個副本 

 

  
  
  

 

  
  $ kubectl scale deployment/my-nginx --replicas= 
 
  1 

 

  
  
  

 

  
  deployment 
 
  "my-nginx" scaled 

 

  
  
  

 

  
  $ kubectl scale deployment my-nginx --replicas= 
 
  1 
 
  # 做用效果等同上一條命令

deployment的更新回滾

Alt text

 

  
  $ kubectl create -f nginx.yaml 

 

  
  
  

 

  
  $ kubectl get pod 

 

  
  
  

 

  
  NAME READY STATUS RESTARTS AGE 

 

  
  
  

 

  
  my-nginx- 
 
  4087004473- 
 
  4xj74 
 
  1/ 
 
  1 Running 
 
  0 
 
  3m 

 

  
  
  

 

  
  my-nginx- 
 
  4087004473-jkptq 
 
  1/ 
 
  1 Running 
 
  0 
 
  3m 

 

  
  
  

 

  
  my-nginx- 
 
  4087004473-m55s1 
 
  1/ 
 
  1 Running 
 
  0 
 
  3m 

 

  
  
  

 

  
  $ kubectl get deployment 

 

  
  
  

 

  
  NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE 

 

  
  
  

 

  
  my-nginx 
 
  3 
 
  3 
 
  3 
 
  3 
 
  4m 

 

  
  
  

 
 
 
  # 更新應用的鏡像從1.7.9版本——>1.9.1 

 

  
  
  

 

  
  $ kubectl set image deployment/my-nginx nginx=nginx: 
 
  1.9. 
 
  1 

 

  
  
  

 

  
  deployment 
 
  "my-nginx" image updated 

 

  
  
  

 
 
 
  # 確認是否更新成功 

 

  
  
  

 

  
  $ kubectl rollout status deployment/my-nginx 

 

  
  
  

 

  
  deployment 
 
  "my-nginx" successfully rolled out 

 

  
  
  

 
 
 
  # 回滾到上一代版本 

 

  
  
  

 

  
  $ kubectl rollout undo deployment/my-nginx 

 

  
  
  

 

  
  deployment 
 
  "my-nginx" rolled back

ConfigMap-容器應用的配置管理

應用部署的一個最佳實踐是將應用所需配置信息和程序進行分離，一則程序能夠更好的複用，二則能靈活的更改配置從而實現其餘功能。

使用configMap替代環境變量

以yaml文件方式建立ConfigMap

 
 
 
  # vi special-config.yaml 

 

  
  
  

 
 

 

  
  
  

 
 
 
  apiVersion: 
 
  v1 

 

  
  
  

 
 
 
  kind: 
 
  ConfigMap 

 

  
  
  

 
 
 
  metadata: 

 

  
  
  

 
 
 
   name: 
 
  special-config 

 

  
  
  

 
 
 
   namespace: 
 
  default 

 

  
  
  

 
 
 
  data: 

 

  
  
  

 
 
 
  special.how: 
 
  very 

 

  
  
  

 
 
 
  special.type: 
 
  charm 

 
 
 
 
  # vi env-config.yaml 

 

  
  
  

 
 

 

  
  
  

 
 
 
  apiVersion: 
 
  v1 

 

  
  
  

 
 
 
  kind: 
 
  ConfigMap 

 

  
  
  

 
 
 
  metadata: 

 

  
  
  

 
 
 
   name: 
 
  env-config 

 

  
  
  

 
 
 
   namespace: 
 
  default 

 

  
  
  

 
 
 
  data: 

 

  
  
  

 
 
 
   log_level: 
 
  INFO

能夠在Pod中這樣使用ConfigMap

 
 
 
  # vi configMap.yaml 

 

  
  
  

 
 

 

  
  
  

 
 
 
  apiVersion: 
 
  v1 

 

  
  
  

 
 
 
  kind: 
 
  Pod 

 

  
  
  

 
 
 
  metadata: 

 

  
  
  

 
 
 
   name: 
 
  dapi-test-pod 

 

  
  
  

 
 
 
  spec: 

 

  
  
  

 
 
 
   containers: 

 

  
  
  

 
 
 
   - name: 
 
  test-container 

 

  
  
  

 
 
 
   image: 
 
  nginx 

 

  
  
  

 
 
 
   command: 
 
  [ 
 
  "/bin/sh" 
 
  , 
 
  "-c" 
 
  , 
 
  "env" 
 
  ] 

 

  
  
  

 
 
 
   env: 

 

  
  
  

 
 
 
   - name: 
 
  SPECIAL_LEVEL_KEY 
 
  #定義環境變量名稱 

 

  
  
  

 
 
 
   valueFrom: 
 
  #key"special.how"對應的值 

 

  
  
  

 
 
 
   configMapKeyRef: 

 

  
  
  

 
 
 
   name: 
 
  special-config 
 
  #環境變量的值 

 

  
  
  

 
 
 
   key: 
 
  special.how 

 

  
  
  

 
 
 
   - name: 
 
  SPECIAL_TYPE_KEY 

 

  
  
  

 
 
 
   valueFrom: 

 

  
  
  

 
 
 
   configMapKeyRef: 

 

  
  
  

 
 
 
   name: 
 
  special-config 

 

  
  
  

 
 
 
   key: 
 
  special.type 

 

  
  
  

 
 
 
   restartPolicy: 
 
  Never

啓動等一系列操做

 

  
  $ kubectl create -f special-config.yaml 

 

  
  
  

 

  
  configmap 
 
  "special-config" created 

 

  
  
  

 

  
  $ kubectl create -f env-config.yaml 

 

  
  
  

 

  
  configmap 
 
  "env-config" created 

 

  
  
  

 
 
 
  # 查看ConfigMap 

 

  
  
  

 

  
  $ kubectl get configmaps 

 

  
  
  

 

  
  NAME 
 
  DATA AGE 

 

  
  
  

 

  
  env-config 
 
  1 
 
  38m 

 

  
  
  

 

  
  special-config 
 
  2 
 
  39m 

 

  
  
  

 
 
 
  # 讓咱們看一下建立的ConfigMap 

 

  
  
  

 

  
  $ kubectl describe configmap env-config 

 

  
  
  

 

  
  Name: env-config 

 

  
  
  

 

  
  Namespace: default 

 

  
  
  

 

  
  Labels: <none> 

 

  
  
  

 

  
  Annotations: <none> 

 

  
  
  

 
 

 

  
  
  

 
 
 
  Data 

 

  
  
  

 

  
  ==== 

 

  
  
  

 

  
  log_level: 
 
  4 bytes 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # 查看ConfigMap鍵的值 

 

  
  
  

 

  
  $ kubectl get configmaps env-config -o yaml 

 

  
  
  

 

  
  apiVersion: v1 

 

  
  
  

 
 
 
  data: 

 

  
  
  

 

  
  log_level: INFO 

 

  
  
  

 

  
  kind: ConfigMap 

 

  
  
  

 

  
  metadata: 

 

  
  
  

 

  
  creationTimestamp: 
 
  2017- 
 
  11- 
 
  30T07: 
 
  29: 
 
  49Z 

 

  
  
  

 

  
  name: env-config 

 

  
  
  

 

  
  namespace: default 

 

  
  
  

 

  
  resourceVersion: 
 
  "285268" 

 

  
  
  

 

  
  selfLink: /api/v1/namespaces/default/configmaps/env-config 

 

  
  
  

 

  
  uid: 
 
  3f473adf-d5a0- 
 
  11e7- 
 
  9830- 
 
  0800275ae9e7

​

 

  
  $ kubectl create -f configMap.yaml 

 

  
  
  

 

  
  pod 
 
  "dapi-test-pod" created 

 

  
  
  

 
 
 
  # 查看pod，狀態ContainerCreating 

 

  
  
  

 

  
  $ kubectl get pod 

 

  
  
  

 

  
  NAME READY STATUS RESTARTS AGE 

 

  
  
  

 

  
  dapi-test-pod 
 
  0/ 
 
  1 ContainerCreating 
 
  0 
 
  3s 

 

  
  
  

 
 
 
  # 隔一段時間再查看pod,發現並無返回什麼 

 

  
  
  

 

  
  $ kubectl get pod 

 

  
  
  

 
 
 
  # 顯示全部的權限查看pod 

 

  
  
  

 

  
  $ kubectl get pod --show-all 

 

  
  
  

 

  
  NAME READY STATUS RESTARTS AGE 

 

  
  
  

 

  
  dapi-test-pod 
 
  0/ 
 
  1 Completed 
 
  0 
 
  1m 

 

  
  
  

 
 
 
  # 查看詳情 

 

  
  
  

 

  
  $ kubectl describe pod dapi-test-pod 

 

  
  
  

 

  
  Name: dapi-test-pod 

 

  
  
  

 

  
  Namespace: default 

 

  
  
  

 

  
  Node: 
 
  127.0. 
 
  0.1/ 
 
  127.0. 
 
  0.1 

 

  
  
  

 

  
  Start Time: Thu, 
 
  30 Nov 
 
  2017 
 
  15: 
 
  32: 
 
  00 + 
 
  0800 

 

  
  
  

 

  
  Labels: <none> 

 

  
  
  

 

  
  Status: Succeeded 

 

  
  
  

 

  
  IP: 

 

  
  
  

 

  
  Controllers: <none> 

 

  
  
  

 

  
  Containers: 

 

  
  
  

 

  
  test-container: 

 

  
  
  

 

  
  Container ID: docker:// 
 
  1ba533f43ee60c02e03dafb7bcb8495fc12264aaab229872df0b289a3c1b9976 

 

  
  
  

 

  
  Image: nginx 

 

  
  
  

 

  
  Image ID: docker-pullable://docker.io/nginx@sha256:b81f317384d7388708a498555c28a7cce778a8f291d90021208b3eba3fe74887 

 

  
  
  

 

  
  Port: 

 

  
  
  

 

  
  Command: 

 

  
  
  

 

  
  /bin/sh 

 

  
  
  

 

  
  -c 

 

  
  
  

 

  
  env 

 

  
  
  

 

  
  State: Terminated 

 

  
  
  

 

  
  Reason: Completed 

 

  
  
  

 
 
 
  Exit Code: 
 
  0 

 

  
  
  

 

  
  Started: Thu, 
 
  30 Nov 
 
  2017 
 
  15: 
 
  32: 
 
  25 + 
 
  0800 

 

  
  
  

 

  
  Finished: Thu, 
 
  30 Nov 
 
  2017 
 
  15: 
 
  32: 
 
  25 + 
 
  0800 

 

  
  
  

 

  
  Ready: False 

 

  
  
  

 

  
  Restart Count: 
 
  0 

 

  
  
  

 

  
  Volume Mounts: <none> 

 

  
  
  

 

  
  Environment Variables: 

 

  
  
  

 

  
  SPECIAL_LEVEL_KEY: <set to the key 
 
  'special.how' of config map 
 
  'special-config'> 

 

  
  
  

 

  
  SPECIAL_TYPE_KEY: <set to the key 
 
  'special.type' of config map 
 
  'special-config'> 

 

  
  
  

 

  
  Conditions: 

 

  
  
  

 

  
  Type Status 

 

  
  
  

 

  
  Initialized True 

 

  
  
  

 

  
  Ready False 

 

  
  
  

 

  
  PodScheduled True 

 

  
  
  

 

  
  No volumes. 

 

  
  
  

 

  
  QoS Class: BestEffort 

 

  
  
  

 

  
  Tolerations: <none> 

 

  
  
  

 

  
  Events: 

 

  
  
  

 

  
  FirstSeen LastSeen Count From SubObjectPath Type Reason Message 

 

  
  
  

 

  
  --------- -------- ----- ---- ------------- -------- ------ ------- 

 

  
  
  

 
 
 
  3m 
 
  3m 
 
  1 {default-scheduler } Normal Scheduled Successfully assigned dapi-test-pod to 
 
  127.0. 
 
  0.1 

 

  
  
  

 
 
 
  3m 
 
  3m 
 
  1 {kubelet 
 
  127.0. 
 
  0.1} spec.containers{test-container} Normal Pulling pulling image 
 
  "nginx" 

 

  
  
  

 
 
 
  3m 
 
  2m 
 
  2 {kubelet 
 
  127.0. 
 
  0.1} Warning MissingClusterDNS kubelet does not have ClusterDNS IP configured and cannot create Pod using 
 
  "ClusterFirst" policy. Falling back to DNSDefault policy. 

 

  
  
  

 
 
 
  2m 
 
  2m 
 
  1 {kubelet 
 
  127.0. 
 
  0.1} spec.containers{test-container} Normal Pulled Successfully pulled image 
 
  "nginx" 

 

  
  
  

 
 
 
  2m 
 
  2m 
 
  1 {kubelet 
 
  127.0. 
 
  0.1} spec.containers{test-container} Normal Created Created container with docker id 
 
  1ba533f43ee6; Security:[seccomp=unconfined] 

 

  
  
  

 
 
 
  2m 
 
  2m 
 
  1 {kubelet 
 
  127.0. 
 
  0.1} spec.containers{test-container} Normal Started Started container with docker id 
 
  1ba533f43ee6 

 

  
  
  

 
 
 
  # 可知container started 成功，進一步查看日誌 

 

  
  
  

 

  
  $ docker logs 
 
  1ba 

 

  
  
  

 

  
  KUBERNETES_SERVICE_PORT= 
 
  443 

 

  
  
  

 

  
  KUBERNETES_PORT=tcp:// 
 
  10.254. 
 
  0.1: 
 
  443 

 

  
  
  

 

  
  MY_SERVICE_PORT_80_TCP=tcp:// 
 
  10.254. 
 
  110.249: 
 
  80 

 

  
  
  

 

  
  MY_SERVICE_PORT_443_TCP_ADDR= 
 
  10.254. 
 
  110.249 

 

  
  
  

 

  
  HOSTNAME=dapi-test-pod 

 

  
  
  

 

  
  MY_SERVICE_PORT_443_TCP_PORT= 
 
  443 

 

  
  
  

 

  
  HOME=/root 

 

  
  
  

 

  
  MY_SERVICE_PORT_443_TCP_PROTO=tcp 

 

  
  
  

 

  
  MY_SERVICE_SERVICE_PORT_HTTP= 
 
  80 

 

  
  
  

 

  
  SPECIAL_TYPE_KEY=charm 

 

  
  
  

 

  
  MY_SERVICE_SERVICE_PORT_HTTPS= 
 
  443 

 

  
  
  

 

  
  MY_SERVICE_PORT_443_TCP=tcp:// 
 
  10.254. 
 
  110.249: 
 
  443 

 

  
  
  

 

  
  MY_SERVICE_SERVICE_HOST= 
 
  10.254. 
 
  110.249 

 

  
  
  

 

  
  KUBERNETES_PORT_443_TCP_ADDR= 
 
  10.254. 
 
  0.1 

 

  
  
  

 

  
  NGINX_VERSION= 
 
  1.13. 
 
  7- 
 
  1~stretch 

 

  
  
  

 

  
  PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin 

 

  
  
  

 

  
  KUBERNETES_PORT_443_TCP_PORT= 
 
  443 

 

  
  
  

 

  
  NJS_VERSION= 
 
  1.13. 
 
  7.0. 
 
  1.15- 
 
  1~stretch 

 

  
  
  

 

  
  KUBERNETES_PORT_443_TCP_PROTO=tcp 

 

  
  
  

 

  
  MY_SERVICE_SERVICE_PORT= 
 
  80 

 

  
  
  

 

  
  MY_SERVICE_PORT=tcp:// 
 
  10.254. 
 
  110.249: 
 
  80 

 

  
  
  

 

  
  SPECIAL_LEVEL_KEY=very 

 

  
  
  

 

  
  MY_SERVICE_PORT_80_TCP_ADDR= 
 
  10.254. 
 
  110.249 

 

  
  
  

 

  
  KUBERNETES_PORT_443_TCP=tcp:// 
 
  10.254. 
 
  0.1: 
 
  443 

 

  
  
  

 

  
  KUBERNETES_SERVICE_PORT_HTTPS= 
 
  443 

 

  
  
  

 

  
  KUBERNETES_SERVICE_HOST= 
 
  10.254. 
 
  0.1 

 

  
  
  

 

  
  MY_SERVICE_PORT_80_TCP_PORT= 
 
  80 

 

  
  
  

 

  
  PWD=/ 

 

  
  
  

 

  
  MY_SERVICE_PORT_80_TCP_PROTO=tcp

​

ConfigMap的限制條件

  • ConfigMap必須在Pod以前建立才能被使用。
  • ConfigMap能夠定義其屬於哪一個Namspece，只有在同一個Namespace中的pod才能引用。

刪除Pod

  • 有時候deployment、rs、rc、services都爲0，可是Pod確存在着。則重啓kubelet服務便可。
 

  
  $ systemctl restart kubelet

補充

 
 
 
  # 列出當前節點名 

 

  
  
  

 

  
  kubectl get node 

 

  
  
  

 

  
  NAME STATUS AGE 

 

  
  
  

 
 
 
  127.0. 
 
  0.1 Ready 
 
  6d 

 

  
  
  

 
 
 
  # 已知當前節點名爲127.0.0.1,用以下命令便可得到該節點上全部運行節點 

 

  
  
  

 

  
  $ curl localhost: 
 
  8080/api/v1/proxy/nodes/ 
 
  127.0. 
 
  0.1/pods 

 

  
  
  

 

  
  { 
 
  "kind": 
 
  "PodList", 
 
  "apiVersion": 
 
  "v1", 
 
  "metadata":{}, 
 
  "items":null}

報錯

 

  
  $ sudo kubectl create -f file.yaml 

 

  
  
  

 

  
  YAML error: found character that cannot start any token 

 

  
  
  

 
 
 
  # or 

 

  
  
  

 

  
  error:yaml: line 
 
  15: found a tab character that violate indentation 

 

  
  
  

 
 

 

  
  
  

 
 
 
  #file.yaml不可用tab鍵來空格 

 

  
  
  

 
 

 

  
  
  

 

  
  $ sudo kubectl create -f mysql-rc.yaml 

 

  
  
  

 

  
  error: error validating 
 
  "mysql-rc.yaml": error validating 
 
  data: [found invalid field app 
 
  for v1.ObjectMeta, found invalid field value 
 
  for v1.Container]; 
 
  if you choose to ignore these errors, turn validation off with --validate=false 

 

  
  
  

 
 

 

  
  
  

 
 

 

  
  
  

 
 

 

  
  
  

 
 

 

  
  
  

 

  
  --------------------- 

 

  
  
  

 
 

 

  
  
  

 
 
 
  # kubectl get pod --all-namespaces 

 

  
  
  

 

  
  NAMESPACE NAME READY STATUS RESTARTS AGE 

 

  
  
  

 

  
  default my-nginx- 
 
  379829228-b796w 
 
  1/ 
 
  1 Running 
 
  0 
 
  12m 

 

  
  
  

 

  
  kube-system kubernetes-dashboard- 
 
  2397086622- 
 
  46tvx 
 
  0/ 
 
  1 ContainerCreating 
 
  0 
 
  8s 

 

  
  
  

 
 

 

  
  
  

 

  
  [root@node01 ~] 
 
  # kubectl logs -f kubernetes-dashboard-2397086622-46tvx --namespace=kube-system  

 

  
  
  

 

  
  Using HTTP port: 
 
  9090 

 

  
  
  

 

  
  Using apiserver-host location: http:// 
 
  127.0. 
 
  0.1: 
 
  8080 

 

  
  
  

 

  
  Creating API server client 
 
  for http:// 
 
  127.0. 
 
  0.1: 
 
  8080 

 

  
  
  

 

  
  Error 
 
  while initializing connection to Kubernetes apiserver. This most likely means that the cluster is misconfigured (e.g., it has invalid apiserver certificates or service accounts configuration) or the --apiserver-host 
 
  param points to a server that does not exist. Reason: Get http:// 
 
  127.0. 
 
  0.1: 
 
  8080/version: dial tcp 
 
  127.0. 
 
  0.1: 
 
  8080: getsockopt: connection refused 

 

  
  
  

 

  
  Refer to the troubleshooting guide 
 
  for more information: https://github.com/kubernetes/dashboard/blob/master/docs/user-guide/troubleshooting.md
咱們最好不要越過RC而直接建立Pod,由於Replication Controller會經過RC管理Pod副本。實現自動建立、補足、替換、刪除Pod副本，大大提升系統的容災能力
  • 從新調度(Rescheduling)
  • 彈性伸縮(Scaling)
  • 滾動更新(Rolling Updates)
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