docker-compose.yml

version: "3"

#虚拟网络配置，分配虚拟IP地址，当前配置使容器之间组成局域网(与driver的选择有关)
networks:
  my-net:
    driver: bridge
    ipam:
      driver: default
      config:
        - subnet: 192.168.0.0/24   #设置子网地址空间(容器IP范围)

services:

  nginx:
    image: nginx
    container_name: "mynginx"
    networks:
      my-net:
        ipv4_address: 192.168.0.2 #指定nginx容器IP地址
    ports:
      - "80:80" #对主机80端口的访问会映射到容器的80端口
    volumes:
      - /usr/local/docker/docker-compose/nginx/nginx.conf:/etc/nginx/nginx.conf
      - /usr/local/docker/docker-compose/nginx/log:/var/log/nginx
      - /usr/local/docker/docker-compose/nginx/html:/usr/share/nginx/html
    #tomcat启动完成再启动nginx
    depends_on:
      - tomcat-1
      - tomcat-2
      - tomcat-3

  tomcat-1:
    image: tomcat
    container_name: "mytomcat-1"
    networks:
      my-net:
        ipv4_address: 192.168.0.3
    ports:
      - "8081:8080"
    restart: "always"
    volumes:
      - /usr/local/docker/docker-compose/tomcat-cluster/tomcat-1/conf:/usr/local/tomcat/conf
      - /usr/local/docker/docker-compose/tomcat-cluster/tomcat-1/logs:/usr/local/tomcat/logs
      - /usr/local/docker/docker-compose/tomcat-cluster/tomcat-1/webapps:/usr/local/tomcat/webapps

  tomcat-2:
    image: tomcat
    container_name: "mytomcat-2"
    networks:
      my-net:
        ipv4_address: 192.168.0.4
    ports:
      - "8082:8080"
    restart: "always"
    volumes:
      - /usr/local/docker/docker-compose/tomcat-cluster/tomcat-2/conf:/usr/local/tomcat/conf
      - /usr/local/docker/docker-compose/tomcat-cluster/tomcat-2/logs:/usr/local/tomcat/logs
      - /usr/local/docker/docker-compose/tomcat-cluster/tomcat-2/webapps:/usr/local/tomcat/webapps

  tomcat-3:
    image: tomcat
    container_name: "mytomcat-3"
    networks:
      my-net:
        ipv4_address: 192.168.0.5
    ports:
      - "8083:8080"
    restart: "always"
    volumes:
      - /usr/local/docker/docker-compose/tomcat-cluster/tomcat-3/conf:/usr/local/tomcat/conf
      - /usr/local/docker/docker-compose/tomcat-cluster/tomcat-3/logs:/usr/local/tomcat/logs
      - /usr/local/docker/docker-compose/tomcat-cluster/tomcat-3/webapps:/usr/local/tomcat/webapps

Nginx配置文件nginx.conf


user  nginx;
worker_processes  1;

error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    keepalive_timeout  65;

    sendfile        on;

	# 需要注意的是如果tomcat都部署在docker内，这里的ip地址填对应docker容器的ip和端口号
	# 注意ip和端口的对应，这里容易把端口号写成宿主机开放的端口号
    upstream tomcat-cluster {
        server 192.168.0.3:8080;
		server 192.168.0.4:8080;
		server 192.168.0.5:8080;
    }

    server {
	    listen       80;
	    server_name  localhost;

	    location / {
	    		proxy_pass http://tomcat-cluster;
	    }


	    # redirect server error pages to the static page.
	    #error_page  404              /404.html;
	    error_page   500 502 503 504  /50x.html;

	    location = /50x.html {
			root   /usr/share/nginx/html;
	    }
	}
}