Docker Compose+nginx实现负载均衡

2018/03/31 Docker

Docker 是一个开源的应用容器引擎,让开发者可以打包他们的应用以及依赖包到一个可移植的容器中,然后发布到任何流行的 Linux 机器上,也可以实现虚拟化。容器是完全使用沙箱机制,相互之间不会有任何接口。

前言

本篇文章引导你使用Docker ComposeDocker容器中运行nginx和两个简单的Spring Boot应用程序,从而实现负载均衡。关于Docker 入门请参考纯洁的微笑Docker 系列文章

准备

  • Docker CE

http://dandandeshangni.oss-cn-beijing.aliyuncs.com/docker/docker_01.png

技术栈

  • Docker
  • Spring Boot
  • NGINX
  • Maven

目录结构

https://raw.githubusercontent.com/longfeizheng/longfeizheng.github.io/master/images/docker/docker01.png

Spring Boot应用程序

pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
       <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.0.RELEASE</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>docker-compose-springboot-nginx</artifactId>

    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-freemarker</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>
DockerController
package cn.merryyou.docker.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;

/**
 * Created on 2018/3/20 0020.
 *
 * @author zlf
 * @email i@merryyou.cn
 * @since 1.0
 */
@Controller
public class DockerController {

    @GetMapping("/")
    public String docker() {
        return "docker";
    }
}

DockerApplication
package cn.merryyou.docker;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

/**
 * Created on 2018/3/20 0020.
 *
 * @author zlf
 * @email i@merryyou.cn
 * @since 1.0
 */
@SpringBootApplication
public class DockerApplication {
    public static void main(String[] args) {
        SpringApplication.run(DockerApplication.class, args);
    }
}


docker.ftl
<h1>Hello Spring Boot with docker-compose!</h1>
application.yml
spring:
  freemarker:
    template-loader-path: classpath:/templates
    request-context-attribute: .ftl
Dockerfile
FROM hub.c.163.com/wuxukun/maven-aliyun:3-jdk-8
ADD ["app-1.jar", "app.jar"]
EXPOSE 8080
ENTRYPOINT ["java","-jar","/app.jar"]
nginx.conf
upstream app {
    server app-1:8080;
    server app-2:8080;
    }

server {
    listen 80;
    charset utf-8;
    access_log off;

    location / {
        proxy_pass http://app;
        proxy_set_header Host $host:$server_port;
        proxy_set_header X-Forwarded-Host $server_name;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }

    location /static {
        access_log   off;
        expires      30d;

        alias /app/static;
    }
}
docker-compose.yaml
version: '2'
services:
  nginx:
   container_name: some-nginx
   image: nginx:1.13
   restart: always
   ports:
   - 80:80
#   - 443:443
   volumes:
   - ./nginx/conf.d:/etc/nginx/conf.d
  app-1:
    restart: always
    build: ./app/docker-app-1
    working_dir: /app
    volumes:
      - ./app:/app
    expose:
      - "8080"
#    command: mvn clean spring-boot:run
    depends_on:
      - nginx
  app-2:
    restart: always
    build: ./app/docker-app-2
    working_dir: /app
    volumes:
      - ./app:/app
    expose:
      - "8080"
#    command: mvn clean spring-boot:run
    depends_on:
      - nginx
  • version: '2': 表示使用第二代语法来构建 docker-compose.yaml 文件;
  • services: 用来表示 compose 需要启动的服务,我们可以看出此文件中有三个服务分别为:nginx、app-1、app-2。
  • container_name:容器名称
  • ports:表示对外开放的端口
  • restart: always:表示如果服务启动不成功会一直尝试。
  • volumes:加载本地目录下的配置文件到容器目标地址下
测试
  • 切换到docker-compose-boot-nginx 目录下执行 docker-compose up
  • 访问http://localhost
补充
  1. 如果执行docker-compose up很慢,可在host文件中添加127.0.0.1 localunixsocket.local 参考
  2. docker logs -f -t --tail 行数 容器名查看容器的实时日志

效果如下: https://raw.githubusercontent.com/longfeizheng/longfeizheng.github.io/master/images/docker/docker01.gif

https://raw.githubusercontent.com/longfeizheng/longfeizheng.github.io/master/images/docker/docker02.gif

代码下载

从我的 github 中下载,https://github.com/longfeizheng/docker-compose-boot-nginx


https://raw.githubusercontent.com/longfeizheng/longfeizheng.github.io/master/images/wechat/xiaochengxu.png

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