docker stack

https://docs.docker.com/engine/reference/commandline/stack_deploy/

单机模式下，我们可以使用 Docker Compose 来编排多个服务。

Docker Swarm 通过 Docker Stack，只需对已有的 docker-compose.yml 配置文件稍加改造就可以完成 Docker 集群环境下的多服务编排。

stack->task->service

Docker compose示例见： Docker常用操作

myservice-stack.yml

version: "3.4"
services:
  alpine:
    image: alpine # 镜像名称
    command: # 命令
      - "ping"
      - "www.baidu.com"
    networks:
      - "my-overlay" # 指定网络
    deploy:
      replicas: 1 # 负载/实例数量
      restart_policy:
        condition: on-failure
      resources:
        limits:
          cpus: "0.1"
          memory: 50M
    #depends_on: # 会阻塞nginx服务启动？
    #  - nginx
  nginx:
    image: nginx
    networks:
      - "my-overlay"
    ports:
      - "8081:80" # 端口映射
    deploy:
      replicas: 1 # 负载/实例数量
      restart_policy:
        condition: on-failure
      resources:
        limits:
          cpus: "0.1"
          memory: 50M
networks:
  my-overlay: # 网络需先创建好
    external: true

docker stack deploy [OPTIONS] STACK

Deploy a new stack or update an existing stack

  -c, --compose-file 指定compose文件路径，"-"从stdin读取
      --prune 修剪不再被引用的服务
      --resolve-image string 查询resistry服务解析image，always|changed|never(default "always")
      --with-registry-auth 登录registry参数

docker network create -d overlay my-overlay

docker stack deploy -c myservice-stack.yml myservice

docker stack deploy -c myservice-stack.yml myservice
Creating service myservice_nginx
Creating service myservice_alpine

docker stack ls
NAME        SERVICES
myservice   2

docker stack ps myservice
ID             NAME                 IMAGE           NODE            DESIRED STATE   CURRENT STATE                ERROR     PORTS
qig31fucyoj4   myservice_alpine.1   alpine:latest   swarm-manager   Running         Running about a minute ago
pwj4wikgw70i   myservice_nginx.1    nginx:latest    swarm-node2     Running         Running 59 seconds ago

docker stack services myservice
ID             NAME               MODE         REPLICAS   IMAGE           PORTS
w55p2eetzq7d   myservice_alpine   replicated   1/1        alpine:latest
k7g89zs8k68a   myservice_nginx    replicated   1/1        nginx:latest    *:8081->80/tcp