docker service update --publish-add 8080:80 --detach=false nginx

访问： http://192.168.1.19:8080/

http://192.168.1.7:8080/

http://192.168.1.6:8080/

三台节点都可以

扩容 nginx, swarm将会部署成负载均衡

docker service scale nginx=3 --detatch=false

[[email protected] ~]# docker service ls

ID                  NAME                MODE                REPLICAS            IMAGE               PORTS

9iv6vilrha3p        nginx               replicated          3/3                 nginx:latest        *:8080->80/tcp, *:8087->80/tcp

lcuojb81tc0c        nginx1              replicated          1/1                 nginx:latest       

yb6jivpmol4z        test1               replicated          1/1                 alpine:latest     

使用自定义网络部署应用

首先删除 services

[[email protected] ~]# docker service rm nginx nginx1 test1

nginx

nginx1

test1

docker network create -d overlay imooc-overlay

--detach指定后台运行

docker service create --network imooc-overlay -p 8080:80 --detach=false nginx

docker service create --network imooc-overlay --name alpine --detach=false alpine ping www.baidu.com

上alpine所在的机器进入容器内部ping 刚启动的nginx服务（刚才没有给nginx service name, 所以分配了一个随机名称 infallible_brattain）

[email protected] ~]# docker service ps alpine

ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE           ERROR               PORTS

36g8ok640n6t        alpine.1            alpine:latest       slave2              Running             Running 8 minutes ago      

 docker exec -it d04 sh

/ # ping infallible_brattain

PING infallible_brattain (10.0.0.2): 56 data bytes

64 bytes from 10.0.0.2: seq=0 ttl=64 time=0.064 ms

64 bytes from 10.0.0.2: seq=1 ttl=64 time=0.065 ms

64 bytes from 10.0.0.2: seq=2 ttl=64 time=0.066 ms

^C

--- infallible_brattain ping statistics ---

3 packets transmitted, 3 packets received, 0% packet loss

round-trip min/avg/max = 0.064/0.065/0.066 ms

Docker stack 管理一组服务

Service.yml

version: "3.4"

services:

  alpine:

    image: alpine

    command:

      - "ping"

      - "www.baidu.com"

    networks:

      - "imooc-overlay"

    deploy:

      replicas: 2

      restart_policy:

        condition: on-failure

      resources:

        limits:

          cpus: "0.1"

          memory: 50M

    depends_on:

      - nginx

  nginx:

    image: nginx

    networks:

      - "imooc-overlay"

    ports:

      - "8080:80"

networks:

  imooc-overlay:

    external: true

docker stack deploy -c service.yml test

[[email protected] ~]# docker stack ls

NAME                SERVICES            ORCHESTRATOR

test                2                   Swarm

[[email protected] ~]# docker stack services test

ID                  NAME                MODE                REPLICAS            IMAGE               PORTS

1n137ttzosyg        test_nginx          replicated          1/1                 nginx:latest        *:8080->80/tcp

yggli8y0e3tg        test_alpine         replicated          2/2                 alpine:latest  

Docker swarm 负载均衡两种模式，

负载均衡有两种模式：VIP、DNSRR

• VIP：分配独立的虚拟IP，DNS记录解析到服务名中作为代理IP。（如果需要外部直接访问可以采取这种）
• dnsrr：DNS记录不解析VIP，而去解析每个容器内的IP。dnsrr模式不支持端口对外暴露。（如果不需要外部访问，只是微服务组件之间的通讯可以考虑这种）

其他资料参考

https://www.cnblogs.com/xiangsikai/p/9938862.html