Docker+Nginx+Tomcat配置简单的负载均衡

环境说明

虚拟机 Centos7 IP 192.168.1.144
[root@master ~]# uname -a
Linux master 3.10.0-514.el7.x86_64 #1 SMP Tue Nov 22 16:42:41 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

Nginx安装

yum install nginx

nginx -v
nginx version: nginx/1.12.2

Docker安装

yum install -y yum-utils device-mapper-persistent-data lvm2
yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
yum -y install docker-ce
systemctl start docker

docker version
Client:
 Version:           18.09.4
 API version:       1.39
 Go version:        go1.10.8
 Git commit:        d14af54266
 Built:             Wed Mar 27 18:34:51 2019
 OS/Arch:           linux/amd64
 Experimental:      false

Server: Docker Engine - Community
 Engine:
  Version:          18.09.4
  API version:      1.39 (minimum version 1.12)
  Go version:       go1.10.8
  Git commit:       d14af54
  Built:            Wed Mar 27 18:04:46 2019
  OS/Arch:          linux/amd64
  Experimental:     false

Docker运行tomcat实例

[root@master ~]# docker pull tomcat
[root@master ~]# docker images
REPOSITORY           TAG                 IMAGE ID            CREATED             SIZE
tomcat               latest              f1332ae3f570        5 days ago          463MB
#创建docker连接目录
[root@master ~]# mkdir 4480
[root@master ~]# mkdir 5580
#运行4480实例
[root@master ~]# docker run --name tomcat44 -p 4480:8080 -v /root/4480:/usr/local/tomcat/webapps/ROOT -d tomcat
#运行5580实例
[root@master ~]# docker run --name tomcat55 -p 5580:8080 -v /root/5580:/usr/local/tomcat/webapps/ROOT -d tomcat
#检查
[root@master ~]# netstat -antp
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
tcp6       0      0 :::5580                 :::*                    LISTEN      31560/docker-proxy  
tcp6       0      0 :::4480                 :::*                    LISTEN      31385/docker-proxy  
#创建index文件
[root@master ~]# cd /root/4480
[root@master 4480]# echo 4480 > index.html
[root@master ~]# cd /root/5580
[root@master 5580]# echo 5580 > index.html

测试

访问 http://192.168.1.144:4480/
4480
访问 http://192.168.1.144:5580/
5580

Nginx 负载均衡

[root@master ~]# vi /etc/nginx/nginx.conf

在http节点中(大概40行 :40)增加如下内容：

       server {
                listen 80;
                server_name 192.168.1.144;
                location  / {
                        proxy_pass http://tomcat;
                }
        }
        upstream tomcat{
                server localhost:4480 weight=5;
                server localhost:5580 weight=5;
        }

#启动Ngixn
[root@master ~]# systemctl start nginx

测试

访问 http://192.168.1.144
4480或5580
这时刷新就会发现内容会在4480和5580之间切换。
这样就达到了负载均衡。