玩转spring boot——结合docker
前言
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 liunx 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。Docker 自 2013 年以来非常火热，因为它能把开发、测试、运维紧密的联系起来。spring boot 又能很好的融合 Docker，让我们看一下 spring boot 是怎样与 Docker 结合的吧。
一、创建新项目
pom.xml
<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"> <modelVersion>4.0.0</modelVersion><span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span>com.github.carter659<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span>spring12<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">version</span><span style="color: rgba(0, 0, 255, 1)">></span>0.0.1-SNAPSHOT<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">version</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">packaging</span><span style="color: rgba(0, 0, 255, 1)">></span>jar<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">packaging</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">></span>spring12<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">url</span><span style="color: rgba(0, 0, 255, 1)">></span>http://maven.apache.org<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">url</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">parent</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span>org.springframework.boot<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span>spring-boot-starter-parent<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">version</span><span style="color: rgba(0, 0, 255, 1)">></span>1.4.3.RELEASE<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">version</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">parent</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">properties</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">project.build.sourceEncoding</span><span style="color: rgba(0, 0, 255, 1)">></span>UTF-8<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">project.build.sourceEncoding</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">java.version</span><span style="color: rgba(0, 0, 255, 1)">></span>1.8<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">java.version</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">docker.image.prefix</span><span style="color: rgba(0, 0, 255, 1)">></span>springboot<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">docker.image.prefix</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">properties</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">dependencies</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">dependency</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span>org.springframework.boot<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span>spring-boot-starter-web<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">dependency</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">dependencies</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">build</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">plugins</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">plugin</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span>org.springframework.boot<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span>spring-boot-maven-plugin<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">plugin</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">plugin</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span>com.spotify<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span>docker-maven-plugin<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">version</span><span style="color: rgba(0, 0, 255, 1)">></span>0.4.11<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">version</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">configuration</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">imageName</span><span style="color: rgba(0, 0, 255, 1)">></span>${docker.image.prefix}/${project.artifactId}<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">imageName</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">dockerDirectory</span><span style="color: rgba(0, 0, 255, 1)">></span>src/main/docker<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">dockerDirectory</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">resources</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">resource</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">targetPath</span><span style="color: rgba(0, 0, 255, 1)">></span>/<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">targetPath</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">directory</span><span style="color: rgba(0, 0, 255, 1)">></span>${project.build.directory}<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">directory</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">include</span><span style="color: rgba(0, 0, 255, 1)">></span>${project.build.finalName}.jar<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">include</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">resource</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">resources</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">configuration</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">plugin</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">plugins</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">finalName</span><span style="color: rgba(0, 0, 255, 1)">></span>spring12<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">finalName</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">build</span><span style="color: rgba(0, 0, 255, 1)">></span></project>
properties 节点中设置 docker 镜像的前缀“springboot”：
<docker.image.prefix>springboot</docker.image.prefix>
加入 maven 插件“docker-maven-plugin”：
<plugin> <groupId>com.spotify</groupId> <artifactId>docker-maven-plugin</artifactId> <version>0.4.11</version> <configuration> <imageName>${docker.image.prefix}/${project.artifactId}</imageName> <dockerDirectory>src/main/docker</dockerDirectory> <resources> <resource> <targetPath>/</targetPath> <directory>${project.build.directory}</directory> <include>${project.build.finalName}.jar</include> </resource> </resources> </configuration> </plugin>
package com.github.carter659.spring12;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;/**
*/
@SpringBootApplication
@RestController
public class App {</span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> main(String[] args) { SpringApplication.run(App.</span><span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">, args); } @GetMapping(</span>"/"<span style="color: rgba(0, 0, 0, 1)">) </span><span style="color: rgba(0, 0, 255, 1)">public</span><span style="color: rgba(0, 0, 0, 1)"> String index() { </span><span style="color: rgba(0, 0, 255, 1)">return</span> "你好,docker"<span style="color: rgba(0, 0, 0, 1)">; }}
创建“src/main/docker/Dockerfile”文件：
FROM frolvlad/alpine-oraclejdk8:slim VOLUME /tmp ADD spring12.jar app.jar RUN sh -c 'touch /app.jar' ENV JAVA_OPTS=""ENTRYPOINT ["sh","-c","java $JAVA_OPTS -Djava.security.egd=file:/dev/./urandom -jar /app.jar"]
FROM 为使用哪个镜像
VOLUME 为挂载路径
ADD 为复制文件到镜像中
RUN 为初始化时运行的命令
ENV 为设置环境变量
ENTRYPOINT 为启动时运行的命令
项目结构如图：
二、部署 Docker
选择一个 linux 系统，如 ubuntu 或 centos，在此之前需安装 jdk 和 maven
1. 安装 docker 环境：
ubuntu 为：
$ apt-get install docker.io -y
centos 为：
$ yum install docker-io -y
2. 生成镜像
下面以 ubuntu 为例
$ mvn package docker:build
3. 查看镜像
$ docker images
发现了“springboot/spring12”，
其中“springboot”是之前设置的 docker 镜像前缀“<docker.image.prefix>springboot</docker.image.prefix>”，
“spring12”是生成的文件名“<finalName>spring12</finalName>”，这些都在 pom.xml 中设置。
4. 运行镜像
$ docker run -p 8080:8080 -t springboot/spring12
输入网址测试：
docker 的部署基本完成了，在生成镜像后也可以加入“-DpushImage”参数，再生成完毕的时候把镜像推送的镜像仓库中
$ mvn package docker:build -DpushImage
总结
上述的实现方式并不完美，实际项目中还需要让 spring boot 应用在后台运行，并且能实现启动服务器后自动启动 docker 容器。其思路是，通常会使用 supervisord 来辅助完成，思路是在 supervisord 的配置文件中执行 shell 脚本。然而这同样不完美，而最好的做法是实现“持续集成”，其思路是使用 jenkins 来结合 git 钩子，当提交新版本的代码后，jenkins 去执行 shell 脚本 pull 代码，然后 maven 打包，接下来生成最新版的 docker 镜像，最后推送新镜像和运行 docker 容器。
参考官方文档：http://spring.io/guides/gs/spring-boot-docker/
代码：https://github.com/carter659/spring-boot-12.git
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