创建docker swarm应用

下面以docker官网上的创建vote投票示例来说明如何创建一个docker swarm的应用。

在进行如下步骤时，你需要保证已经部署并正常运行着一个docker swarm集群。

在这个应用中你将学到

  • 通过创建docker-stack.yml和使用docker stack deploy命令来部署应用
  • 使用visualizer来查看应用的运行时
  • 更新docker-stack.yml和vote镜像重新部署和发布vote 应用
  • 使用Compose Version 3

vote-app-diagram

需要使用到的images

Service 描述 Base image
vote Presents the voting interface via port 5000. Viewable at :5000 Based on a Python image, dockersamples/examplevotingapp_vote
result Displays the voting results via port 5001. Viewable at :5001 Based on a Node.js image, dockersamples/examplevotingapp_result
visulizer A web app that shows a map of the deployment of the various services across the available nodes via port 8080. Viewable at :8080 Based on a Node.js image, dockersamples/visualizer
redis Collects raw voting data and stores it in a key/value queue Based on a redis image, redis:alpine
db A PostgreSQL service which provides permanent storage on a host volume Based on a postgres image, postgres:9.4
worker A background service that transfers votes from the queue to permanent storage Based on a .NET image, dockersamples/examplevotingapp_worker

用到的镜像有：

  • dockersamples/examplevotingapp_vote:before
  • dockersamples/examplevotingapp_worker
  • dockersamples/examplevotingapp_result:before
  • dockersamples/visualizer:stable
  • postgres:9.4
  • redis:alpine

我们将这些images同步到我们的私有镜像仓库sz-pg-oam-docker-hub-001.tendcloud.com中。

镜像名称分别为：

  • sz-pg-oam-docker-hub-001.tendcloud.com/library/examplevotingapp_vote:before
  • sz-pg-oam-docker-hub-001.tendcloud.com/library/examplevotingapp_worker
  • sz-pg-oam-docker-hub-001.tendcloud.com/library/examplevotingapp_result:before
  • sz-pg-oam-docker-hub-001.tendcloud.com/library/visualizer:stable
  • sz-pg-oam-docker-hub-001.tendcloud.com/library/postgres:9.4
  • sz-pg-oam-docker-hub-001.tendcloud.com/library/redis:alpine

使用V3版本的compose文件

v3版本的compose与v2版本的区别

docker-stack.yml配置

  1. version: "3"
  2. services:
  4.   redis:
  5.     image: sz-pg-oam-docker-hub-001.tendcloud.com/library/redis:alpine
  6.     ports:
  7.       - "6379"
  8.     networks:
  9.       - frontend
  10.     deploy:
  11.       replicas: 2
  12.       update_config:
  13.         parallelism: 2
  14.         delay: 10s
  15.       restart_policy:
  16.         condition: on-failure
  17.   db:
  18.     image: sz-pg-oam-docker-hub-001.tendcloud.com/library/postgres:9.4
  19.     volumes:
  20.       - db-data:/var/lib/postgresql/data
  21.     networks:
  22.       - backend
  23.     deploy:
  24.       placement:
  25.         constraints: [node.role == manager]
  26.   vote:
  27.     image: sz-pg-oam-docker-hub-001.tendcloud.com/library/examplevotingapp_vote:before
  28.     ports:
  29.       - 5000:80
  30.     networks:
  31.       - frontend
  32.     depends_on:
  33.       - redis
  34.     deploy:
  35.       replicas: 2
  36.       update_config:
  37.         parallelism: 2
  38.       restart_policy:
  39.         condition: on-failure
  40.   result:
  41.     image: sz-pg-oam-docker-hub-001.tendcloud.com/library/examplevotingapp_result:before
  42.     ports:
  43.       - 5001:80
  44.     networks:
  45.       - backend
  46.     depends_on:
  47.       - db
  48.     deploy:
  49.       replicas: 2
  50.       update_config:
  51.         parallelism: 2
  52.         delay: 10s
  53.       restart_policy:
  54.         condition: on-failure
  56.   worker:
  57.     image: sz-pg-oam-docker-hub-001.tendcloud.com/library/examplevotingapp_worker
  58.     networks:
  59.       - frontend
  60.       - backend
  61.     deploy:
  62.       mode: replicated
  63.       replicas: 1
  64.       labels: [APP=VOTING]
  65.       restart_policy:
  66.         condition: on-failure
  67.         delay: 10s
  68.         max_attempts: 3
  69.         window: 120s
  71.   visualizer:
  72.     image: sz-pg-oam-docker-hub-001.tendcloud.com/library/visualizer:stable
  73.     ports:
  74.       - "8080:8080"
  75.     stop_grace_period: 1m30s
  76.     volumes:
  77.       - "/var/run/docker.sock:/var/run/docker.sock"
  78.     deploy:
  79.       placement:
  80.         constraints: [node.role == manager]
  82. networks:
  83.   frontend:
  84.   backend:
  86. volumes:
  87.   db-data:

部署

使用docker stack deploy命令部署vote应用。

  1. $docker stack deploy -c docker-stack.yml vote
  2. Creating network vote_backend
  3. Creating network vote_frontend
  4. Creating network vote_default
  5. Creating service vote_db
  6. Creating service vote_vote
  7. Creating service vote_result
  8. Creating service vote_worker
  9. Creating service vote_visualizer
  10. Creating service vote_redis

使用docker stack deploy部署的应用中的images必须是已经在镜像仓库中存在的，而不能像之前的docker-compose up一样，可以通过本地构建镜像后启动。

使用docker stack service vote查看应用状态

  1. $docker stack services vote
  2. ID            NAME             MODE        REPLICAS  IMAGE
  3. 5bte3o8e0ta9  vote_result      replicated  2/2       sz-pg-oam-docker-hub-001.tendcloud.com/library/examplevotingapp_result:before
  4. h65a6zakqgq3  vote_worker      replicated  1/1       sz-pg-oam-docker-hub-001.tendcloud.com/library/examplevotingapp_worker:latest
  5. k7xzd0adhh52  vote_db          replicated  1/1       sz-pg-oam-docker-hub-001.tendcloud.com/library/postgres:9.4
  6. pvvi5qqcsnag  vote_vote        replicated  2/2       sz-pg-oam-docker-hub-001.tendcloud.com/library/examplevotingapp_vote:before
  7. z4q2gnvoxtpj  vote_redis       replicated  2/2       sz-pg-oam-docker-hub-001.tendcloud.com/library/redis:alpine
  8. zgiuxazk4ssc  vote_visualizer  replicated  1/1       sz-pg-oam-docker-hub-001.tendcloud.com/library/visualizer:stable

使用docker stack ls和docker stack ps vote查看stack的状态

  1. $docker stack ls
  2. NAME  SERVICES
  3. vote  6
  4. $docker stack ps vote
  5. ID            NAME               IMAGE                                                                          NODE                                     DESIRED STATE  CURRENT STATE          ERROR                      PORTS
  6. tcyy62bs26sp  vote_worker.1      sz-pg-oam-docker-hub-001.tendcloud.com/library/examplevotingapp_worker:latest  sz-pg-oam-docker-test-003.tendcloud.com  Running        Running 4 minutes ago                             
  7. tfa84y1yz00j  vote_redis.1       sz-pg-oam-docker-hub-001.tendcloud.com/library/redis:alpine                    sz-pg-oam-docker-test-002.tendcloud.com  Running        Running 5 minutes ago                             
  8. 4yrp8e2pucnu  vote_visualizer.1  sz-pg-oam-docker-hub-001.tendcloud.com/library/visualizer:stable               sz-pg-oam-docker-test-001.tendcloud.com  Running        Running 5 minutes ago                             
  9. zv4dan0n9zo3  vote_worker.1      sz-pg-oam-docker-hub-001.tendcloud.com/library/examplevotingapp_worker:latest  sz-pg-oam-docker-test-003.tendcloud.com  Shutdown       Failed 4 minutes ago   "task: non-zero exit (1)"  
  10. mhbf683hiugr  vote_result.1      sz-pg-oam-docker-hub-001.tendcloud.com/library/examplevotingapp_result:before  sz-pg-oam-docker-test-001.tendcloud.com  Running        Running 5 minutes ago                             
  11. slf6je49r4v1  vote_vote.1        sz-pg-oam-docker-hub-001.tendcloud.com/library/examplevotingapp_vote:before    sz-pg-oam-docker-test-002.tendcloud.com  Running        Running 5 minutes ago                             
  12. mqypecrgriyq  vote_db.1          sz-pg-oam-docker-hub-001.tendcloud.com/library/postgres:9.4                    sz-pg-oam-docker-test-001.tendcloud.com  Running        Running 4 minutes ago                             
  13. 6n7856nsvavn  vote_redis.2       sz-pg-oam-docker-hub-001.tendcloud.com/library/redis:alpine                    sz-pg-oam-docker-test-003.tendcloud.com  Running        Running 5 minutes ago                             
  14. pcrfnm20jf0r  vote_result.2      sz-pg-oam-docker-hub-001.tendcloud.com/library/examplevotingapp_result:before  sz-pg-oam-docker-test-002.tendcloud.com  Running        Running 4 minutes ago                             
  15. ydxurw1jnft6  vote_vote.2        sz-pg-oam-docker-hub-001.tendcloud.com/library/examplevotingapp_vote:before    sz-pg-oam-docker-test-003.tendcloud.com  Running        Running 5 minutes ago

检查

当vote应用成功部署后，在浏览器中访问visualizer所部属到的主机的8080端口http://sz-pg-oam-docker-hub-001.tendcloud.com:8080可以看到如下画面：

visualizer.jpg

Visualizer用于显示服务和主机的状态。

投票界面

在浏览器中访问examplevotingapp_vote所部属到的主机的5000端口http://sz-pg-oam-docker-hub-001.tendcloud.com:5000可以看到如下画面：

vote_web

给猫投一票。cat

结果界面

在浏览器中访问examplevotingapp_result所部属到的主机的5001端口http://sz-pg-oam-docker-hub-001.tendcloud.com:5001可以看到如下画面.

vote_result

总结

至此整个应用已经完整的部署在docker上了，并验证正常运行。

怎么样，是用docker来部署一个应用是不是很简单？

其实后期的维护、升级、扩展都很简单，后面会详细的说明。