使用 docker 部署 java webapp

发表于

本文主要记录一下如何使用 docker 部署 java 的 webapp。

建立 demo webapp

这里为了方便， 使用spring-boot来搭建一个webapp。

首先使用 maven 下载依赖：

<?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">
	<modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.3.1.RELEASE</version>
    </parent>

    <groupId>org.niko.spring.boot</groupId>
	<artifactId>starter-web-docker</artifactId>
	<name>Spring Boot Starter</name>
	<description>Spring Boot Starter</description>
	<url>http://projects.spring.io/spring-boot/</url>

	<organization>
		<name>Pivotal Software, Inc.</name>
		<url>http://www.spring.io</url>
	</organization>

	<properties>
		<main.basedir>${basedir}/../..</main.basedir>
		<java.version>1.8</java.version>
	</properties>

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

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

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
        </dependency>
	</dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>

    </build>

    <!-- Add Spring repositories -->
    <!-- (you don't need this if you are using a .RELEASE version) -->
    <repositories>
        <repository>
            <id>spring-snapshots</id>
            <url>http://repo.spring.io/snapshot</url>
            <snapshots><enabled>true</enabled></snapshots>
        </repository>
        <repository>
            <id>spring-milestones</id>
            <url>http://repo.spring.io/milestone</url>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-snapshots</id>
            <url>http://repo.spring.io/snapshot</url>
        </pluginRepository>
        <pluginRepository>
            <id>spring-milestones</id>
            <url>http://repo.spring.io/milestone</url>
        </pluginRepository>
    </pluginRepositories>
</project>

然后编写 启动器 和 Controller：


import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RestController
public class Application {

    @RequestMapping("/")
    public String home() {
        return "Hello Docker World";
    }

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}

构建包：

mvn package

成功后， target 文件夹下面会有一个 starter-web-docker-1.3.1.RELEASE.jar 文件：

$ ll ./target/
total 15196
drwxrwxr-x 8 niko niko     4096 Nov 13 17:13 ./
drwxrwxr-x 5 niko niko     4096 Nov 13 17:12 ../
drwxrwxr-x 3 niko niko     4096 Nov 13 17:12 classes/
drwxrwxr-x 3 niko niko     4096 Nov 13 17:12 generated-sources/
drwxrwxr-x 3 niko niko     4096 Nov 13 17:12 generated-test-sources/
drwxrwxr-x 2 niko niko     4096 Nov 13 17:13 maven-archiver/
drwxrwxr-x 3 niko niko     4096 Nov 13 17:13 maven-status/
-rw-rw-r-- 1 niko niko 15521233 Nov 13 17:13 starter-web-docker-1.3.1.RELEASE.jar
-rw-rw-r-- 1 niko niko     3594 Nov 13 17:13 starter-web-docker-1.3.1.RELEASE.jar.original
drwxrwxr-x 2 niko niko     4096 Nov 13 17:12 test-classes/

编写 Dockerfile

FROM frolvlad/alpine-oraclejdk8:slim
VOLUME /tmp
ADD starter-web-docker-1.3.1.RELEASE.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" ]

用 docker-maven-plugin 提高生产力

自动生成 image.

<properties>
   <docker.image.prefix>springio</docker.image.prefix>
</properties>
<build>
    <plugins>
        <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>
    </plugins>
</build>

构建 image

现在开始构建 docker image.

$ mvn package docker:build
[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building Spring Boot Starter 1.3.1.RELEASE
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- Docker-maven-plugin:0.4.11:build (default-cli) @ starter-web-docker-hello ---
[INFO] Copying /home/niko/dev/code/java/MavenProj/OpenSources/spring/spring-boot/starter-web-docker/target/starter-web-docker-hello-1.3.1.RELEASE.jar -> /home/niko/dev/code/java/MavenProj/OpenSources/spring/spring-boot/starter-web-docker/target/docker/starter-web-docker-hello-1.3.1.RELEASE.jar
[INFO] Copying src/main/docker/Dockerfile -> /home/niko/dev/code/java/MavenProj/OpenSources/spring/spring-boot/starter-web-docker/target/docker/Dockerfile
[INFO] Building image springio/starter-web-docker-hello
Step 1 : FROM frolvlad/alpine-oraclejdk8:slim
 ---> a290f8607aef
Step 2 : VOLUME /tmp
 ---> Using cache
 ---> c4ed57bbd8e3
Step 3 : ADD starter-web-docker-hello-1.3.1.RELEASE.jar app.jar
 ---> Using cache
 ---> 57c7382f828d
Step 4 : RUN sh -c 'touch /app.jar'
 ---> Using cache
 ---> 37ee84639687
Step 5 : ENV JAVA_OPTS ""
 ---> Using cache
 ---> 3fd3017669ff
Step 6 : ENTRYPOINT sh -c java $JAVA_OPTS -Djava.security.egd=file:/dev/./urandom -jar /app.jar
 ---> Using cache
 ---> e12ac1f796a2
Successfully built e12ac1f796a2
[INFO] Built springio/starter-web-docker-hello
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.745 s

查看 image

构建完成后， 可以查看主机上现有的 images ：

$ docker images
REPOSITORY                          TAG                 IMAGE ID            CREATED             SIZE
springio/starter-web-docker-hello   latest              e12ac1f796a2        5 minutes ago       198.2 MB
frolvlad/alpine-oraclejdk8          slim                a290f8607aef        2 weeks ago         167.2 MB
hello-world                         latest              c54a2cc56cbb        4 months ago        1.848 kB

启动 image

$ docker run -p 8080:8080 -t springio/starter-web-docker-hello:latest

说明：
-p 进行端口映射， 格式为 主机端口:容器端口
-t 分配一个 pseudo-TTY

查看正在运行的 image

$ docker ps
CONTAINER ID        IMAGE                                      COMMAND                  CREATED              STATUS              PORTS                    NAMES
b5154800fbeb        springio/starter-web-docker-hello:latest   "sh -c 'java $JAVA_OP"   About a minute ago   Up About a minute   0.0.0.0:8080->8080/tcp   ecstatic_ardinghelli

可以看到， springio/starter-web-docker-hello:latest 正在运行， 此时打开 localhost:8080 也可以看到 Hello Docker World 的页面消息了。

停止

可以指定 CONTAINER ID 来停止运行。

$ docker stop b5154800fbeb
b5154800fbeb

参考

https://spring.io/guides/gs/spring-boot-docker/