docker-compose实现容器集群编排

docker-compose工具作用

该工具可以编排容器并且让容器可以在集群上执行。

docker-compose安装

[root@ecs-140051 sunpy-docker]# curl -L https://get.daocloud.io/docker/compose/releases/download/1.25.1/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   423  100   423    0     0    538      0 --:--:-- --:--:-- --:--:--   538
100 16.2M  100 16.2M    0     0  9552k      0  0:00:01  0:00:01 --:--:-- 1136k
[root@ecs-140051 sunpy-docker]# docker-compose -version
-bash: /usr/local/bin/docker-compose: Permission denied
[root@ecs-140051 sunpy-docker]# sudo chmod +x /usr/local/bin/docker-compose
[root@ecs-140051 sunpy-docker]# docker-compose -version
docker-compose version 1.25.1, build a82fef07

docker-compose实现nginx反向代理Tomcat

编写tomcat集群和nginx的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
services:
  mynginx:
    image: nginx
    container_name: "mynginx"
    networks:
      my-net:
        ipv4_address: 192.168.0.80 #指定nginx容器IP地址
    ports:
      - "3500:80" #对主机80端口的访问会映射到容器的80端口
    volumes:
      - /home/nginx-conf/nginx.conf:/etc/nginx/nginx.conf
      - /home/nginx-conf/conf:/etc/nginx/conf.d
      - /home/nginx-conf/html:/usr/share/nginx/html
      - /home/nginx-conf/logs:/var/log/nginx
    #tomcat启动完成再启动nginx
    depends_on:
      - tomcat-1
      - tomcat-2
      - tomcat-3
  tomcat-1:
    image: billygoo/tomcat8-jdk8:latest
    container_name: "tomcat-1"
    networks:
      my-net:
        ipv4_address: 192.168.0.81
    ports:
      - "8081:8080"
    restart: "always"
    volumes:
      - /home/tomcat-1/conf:/usr/local/tomcat/conf
      - /home/tomcat-1/logs:/usr/local/tomcat/logs
      - /home/tomcat-1/webapps:/usr/local/tomcat/webapps
  tomcat-2:
    image: billygoo/tomcat8-jdk8:latest
    container_name: "tomcat-2"
    networks:
      my-net:
        ipv4_address: 192.168.0.82
    ports:
      - "8082:8080"
    restart: "always"
    volumes:
      - /home/tomcat-2/conf:/usr/local/tomcat/conf
      - /home/tomcat-2/logs:/usr/local/tomcat/logs
      - /home/tomcat-2/webapps:/usr/local/tomcat/webapps
  tomcat-3:
    image: billygoo/tomcat8-jdk8:latest
    container_name: "tomcat-3"
    networks:
      my-net:
        ipv4_address: 192.168.0.83
    ports:
      - "8083:8080"
    restart: "always"
    volumes:
      - /home/tomcat-3/conf:/usr/local/tomcat/conf
      - /home/tomcat-3/logs:/usr/local/tomcat/logs
      - /home/tomcat-3/webapps:/usr/local/tomcat/webapps

启动集群中的部分服务：

docker-compose -f docker-compose.yml up -d tomcat-1
docker-compose -f docker-compose.yml up -d tomcat-2
docker-compose -f docker-compose.yml up -d tomcat-3
docker-compose -f docker-compose.yml up -d mynginx

配置nginx的配置文件：

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 192.168.0.81:8080;
		server 192.168.0.82:8080;
		server 192.168.0.83:8080;
    }

    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;
	    }
	}
}

注意

1. 在docker-compose在使用volumes挂载容器卷的时候，需要先将挂载的文件和文件夹创建出来，要不然就会无法启动容器。
2. 分配的网段和接口，需要注意是否与docker容器中存在的接口是否会冲突，否则无法启动容器。