Docker容器中基于compose+haproxy搭建负载均衡

一，基本知识

1，Docker Compose

（1）Docker Compose 将所管理的容器分为三层,工程(project),服务(service)以及容器 (contaienr)。
（2）Docker Compose 运行的目录下的所有文件(docker-compose.yml, extends 文件或环境变量文件等)组成一个工程,若无特殊指定工程名即为当前目录名。一个工程当中可包含多个服务,每个服务中定义了容器运行的镜像,参数,依赖。一个服务当中可包括多个容器实例,Docker Compose 并没有解决负载均衡的问题,因此需要借助其他工具实现服务发现及负载均衡。
（3）Docker Compose 是一个用来创建和运行多容器应用的工具。使用 Compose 首先需要编写Compose 文件来描述多个容器服务以及之间的关联,然后通过命令根据配置启动所有的容器。 Dockerfile 可以定义一个容器,而一个 Compose 的模板文件(YAML 格式)可以定义一个 包含多个相互关联容器的应用。

2，使用Compose 基本上分为三步
（1）Dockerfile 定义应用的运行环境
（2）docker-compose.yml 定义组成应用的各服务
（3）docker-compose up 启动整个应用

二、compose部署

1.自己下载的二进制文件移到 /usr/local/bin/，赋予执行权限

[root@server1 hh]# mv docker-compose-Linux-x86_64-1.22.0 /usr/local/bin/docker-compose
[root@server1 hh]# chmod +x /usr/local/bin/docker-compose

2.编写docker-compose.yml

[root@docker1 ~]# cd /tmp
[root@docker1 tmp]# mkdir docker
[root@docker1 tmp]# cd docker/
[root@docker1 docker]# mkdir compose
[root@docker1 docker]# cd compose/
[root@docker1 compose]# vim docker-compose.yml
[root@docker1 compose]# cat docker-compose.yml 
web1:
        image: nginx
        expose:
                - 80
        volumes:
                - ./web1:/usr/share/nginx/html

web2:
        image: nginx
        expose:
                - 80
        volumes:
                - ./web2:/usr/share/nginx/html
haproxy:
        image: haproxy

        volumes:
                - ./haproxy/haproxy.cfg:/usr/local/etc/haproxy/haproxy.cfg:ro

        links:
                - web1
                - web2
        ports:
                - "80:80"
        expose:
                - "80"

3.编写测试用的测试页面

[root@docker1 compose]# mkdir web1
[root@docker1 compose]# mkdir web2
[root@docker1 compose]# echo web1 > web1/index.html      
[root@docker1 compose]# echo web2 > web2/index.html

4.用haproxy实现负载均衡

[root@docker1 compose]# mkdir haproxy          
[root@docker1 compose]# cd haproxy/
[root@docker1 haproxy]# vim haproxy.cfg   
global
        log 127.0.0.1 local0
        log 127.0.0.1 local1 notice
defaults
        log global
        mode http
        option httplog
        option dontlognull
        timeout connect 5000ms
        timeout client 50000ms
        timeout server 50000ms
        stats uri /status

frontend balancer
        bind 0.0.0.0:80
        default_backend web_backends

backend web_backends
        balance roundrobin
        server server1 web1:80 check
        server server2 web2:80 check

5.导入镜像，并运行compose

[root@docker1 ~]# docker load -i nginx.tar 
[root@docker1 ~]# docker load -i haproxy.tar 

[root@docker1 ~]# cd -
/tmp/docker/compose/haproxy
[root@docker1 haproxy]# docker-compose up -d
Creating compose_web1_1 ... done
Creating compose_web2_1 ... done
Creating compose_haproxy_1 ... done
[root@docker1 haproxy]# docker-compose logs  ##可以查看日志记录
Attaching to compose_haproxy_1, compose_web2_1, compose_web1_1
haproxy_1  | <7>haproxy-systemd-wrapper: executing /usr/local/sbin/haproxy -p /run/haproxy.pid -f /usr/local/etc/haproxy/haproxy.cfg -Ds 

6.测试：进入浏览器，输入http://172.25.26.1/
再刷新一下（实现了负载均衡）

访问http://172.25.26.1/status查看负载均衡状态

7.可以在日志记录查看

[root@server1 haproxy]# docker-compose logs 
Attaching to compose_haproxy_1, compose_web1_1, compose_web2_1
haproxy_1  | <7>haproxy-systemd-wrapper: executing /usr/local/sbin/haproxy -p /run/haproxy.pid -f /usr/local/etc/haproxy/haproxy.cfg -Ds 
[root@server1 haproxy]# docker-compose logs 
Attaching to compose_haproxy_1, compose_web1_1, compose_web2_1
web1_1     | 172.17.0.8 - - [03/Jun/2019:10:18:58 +0000] "GET / HTTP/1.1" 200 5 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0" "-"
web1_1     | 172.17.0.8 - - [03/Jun/2019:10:19:02 +0000] "GET / HTTP/1.1" 200 5 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0" "-"
haproxy_1  | <7>haproxy-systemd-wrapper: executing /usr/local/sbin/haproxy -p /run/haproxy.pid -f /usr/local/etc/haproxy/haproxy.cfg -Ds 
web2_1     | 172.17.0.8 - - [03/Jun/2019:10:19:01 +0000] "GET / HTTP/1.1" 200 5 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0" "-"
web2_1     | 172.17.0.8 - - [03/Jun/2019:10:19:08 +0000] "GET / HTTP/1.1" 200 5 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0" "-"

8.compose的关闭，开启，删除和运行
想要删除之前要先关闭

[root@server1 haproxy]# docker-compose ps
      Name                     Command               State         Ports       
-------------------------------------------------------------------------------
compose_haproxy_1   /docker-entrypoint.sh hapr ...   Up      0.0.0.0:80->80/tcp
compose_web1_1      nginx -g daemon off;             Up      80/tcp            
compose_web2_1      nginx -g daemon off;             Up      80/tcp            
[root@server1 haproxy]# docker stop compose_web1_1 	##停止节点1
compose_web1_1
[root@server1 haproxy]# docker-compose ps	##查看服务状态
      Name                     Command               State          Ports       
--------------------------------------------------------------------------------
compose_haproxy_1   /docker-entrypoint.sh hapr ...   Up       0.0.0.0:80->80/tcp
compose_web1_1      nginx -g daemon off;             Exit 0                     
compose_web2_1      nginx -g daemon off;             Up       80/tcp            
[root@server1 haproxy]# docker stop compose_web2_1 
compose_web2_1
[root@server1 haproxy]# docker-compose ps
      Name                     Command               State          Ports       
--------------------------------------------------------------------------------
compose_haproxy_1   /docker-entrypoint.sh hapr ...   Up       0.0.0.0:80->80/tcp
compose_web1_1      nginx -g daemon off;             Exit 0                     
compose_web2_1      nginx -g daemon off;             Exit 0                     
[root@server1 haproxy]#