「走进k8s」Docker三剑客之Docker Swarm（九）

（一）Docker Swarm介绍

• ①Swarm的架构

• ②Swarm的服务和任务

• ③如何部署

1. 直接ssh到manager节点，执行docker命令。
2. 通过远程访问的方式，通过Remote API调用manager上的docker命令，我们这张图画的就是第二种方式。

（二）集群演示

• ①主机信息

• ② manager节点初始化操作（192.168.66.100）

docker swarm init --advertise-addr 192.168.66.100

• ③ 添加worker节点（192.168.66.101）

docker swarm join --token SWMTKN-1-3gfv7tpeznhwsl7v3y0n9f5g7547lgzo7fjpv0pm5s6uzvdlgg-b0mlie5vhp2ms1xg1tyd7zwc2 192.168.66.100:2377

• ④ 添加worker节点（192.168.66.102）

docker swarm join --token SWMTKN-1-3gfv7tpeznhwsl7v3y0n9f5g7547lgzo7fjpv0pm5s6uzvdlgg-b0mlie5vhp2ms1xg1tyd7zwc2 192.168.66.100:2377

• ⑤ manager查看节点

docker node ls

• ⑥ 创建service服务

docker service create --replicas 3 -p 80:80 --name nginx nginx 
docker service ls

docker service ps

• ⑥ 删除service服务

docker service rm nginx

（二）docker swarm 运行docker-compose文件

• ①stack

• ②测试docker-compose文件

mkdir labs
cd labs
vi docker-compose.yml

version: "3"
services:

  redis:
    image: redis:alpine
    ports:
      - "6379"
    networks:
      - frontend
    deploy:
      replicas: 2
      update_config:
        parallelism: 2
        delay: 10s
      restart_policy:
        condition: on-failure

  db:
    image: postgres:9.4
    volumes:
      - db-data:/var/lib/postgresql/data
    networks:
      - backend
    deploy:
      placement:
        constraints: [node.role == manager]

  vote:
    image: dockersamples/examplevotingapp_vote:before
    ports:
      - 5000:80
    networks:
      - frontend
    depends_on:
      - redis
    deploy:
      replicas: 2
      update_config:
        parallelism: 2
      restart_policy:
        condition: on-failure

  result:
    image: dockersamples/examplevotingapp_result:before
    ports:
      - 5001:80
    networks:
      - backend
    depends_on:
      - db
    deploy:
      replicas: 1
      update_config:
        parallelism: 2
        delay: 10s
      restart_policy:
        condition: on-failure

  worker:
    image: dockersamples/examplevotingapp_worker
    networks:
      - frontend
      - backend
    deploy:
      mode: replicated
      replicas: 1
      labels: [APP=VOTING]
      restart_policy:
        condition: on-failure
        delay: 10s
        max_attempts: 3
        window: 120s
      placement:
        constraints: [node.role == manager]

  visualizer:
    image: dockersamples/visualizer:stable
    ports:
      - "8080:8080"
    stop_grace_period: 1m30s
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock"
    deploy:
      placement:
        constraints: [node.role == manager]

networks:
  frontend:
  backend:

volumes:
  db-data:

• ③运行 docker-compose.yml

docker stack deploy example --compose-file=docker-compose.yml
docker stack ls
docker stack services example

• 打开网页
  http:/192.168.66.100:5000/
  http://192.168.66.100:5001/
  http://192.168.66.100:8080/

• 扩展vote

docker service scale example_vote=4

• 删除stack

docker stack rm example

PS：这就是我们的服务编排，都是在三个节点，所谓的编排就是将多个节点变成一个节点来使用，接下来讲的k8s要把docker swarm功能要强大很多，当然也要复杂很多。docker的基本命令一样掌握好！后面说k8s才不会那么吃力，遇到问题了才知道如何解决。