Spring Boot 2.0 (iv): Deploy Spring boot with Docker

Docker technology has been developed to provide a more convenient environment for micro-service landing, the use of Docker deployment Spring Boot is very simple, this article we come to a simple study.

Start by building a simple Spring Boot project, then add Docker support to the project, and finally deploy the project.

A simple Spring Boot project

In pom.xml , use Spring Boot 2.0 related dependencies

<parent>    <groupId>org.springframework.boot</groupId>    <artifactId>spring-boot-starter-parent</artifactId>    <version>2.0.0.RELEASE</version></parent>

Add Web and test dependencies

<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>        <scope>test</scope>    </dependency></dependencies>

Create a Dockercontroller, in which there is a index() method that is returned when accessed:Hello Docker!

@RestControllerpublic class DockerController {    @RequestMapping("/")    public String index() {        return "Hello Docker!";    }}

Start class

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

After the start of the project, after the successful launch, the browser puts the question: http://localhost:8080/ , the page returns: Hello Docker! , the Spring boot project configuration is OK.

Spring Boot Project Add Docker support

pom.xml-propertiesAdd a Docker image name in

<properties>    <docker.image.prefix>springboot</docker.image.prefix></properties>

Add the Docker Build plugin in plugins:

<build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> <!--Docker Mave N Plugin-<plugin> <groupId>com.spotify</groupId> <artifactid>d                Ocker-maven-plugin</artifactid> <version>1.0.0</version> <configuration> <imageName>${docker.image.prefix}/${project.artifactId}</imageName> <dockerdirec                        Tory>src/main/docker</dockerdirectory> <resources> <resource> <targetPath>/</targetPath> <directory>${project.build.directory                    }</directory> <include>${project.build.finalName}.jar</include>     </resource>           </resources> </configuration> </plugin> <!--Docker maven Plugin -</plugins></build>

Create the src/main/docker Dockerfile file in the directory, and the Dockerfile file is used to illustrate how to build the image.

FROM openjdk:8-jdk-alpineVOLUME /tmpADD spring-boot-docker-1.0.jar app.jarENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]

This Dockerfile file is simple, build the JDK infrastructure, add the Spring Boot Jar to the image, and simply explain:

• From, which indicates that the JDK8 environment is used as the base image, and if the mirror is not local, it will be downloaded from DockerHub
• VOLUME, VOLUME points to a /tmp directory, and because Spring Boot uses the built-in Tomcat container, Tomcat is used /tmp as the working directory by default. The effect of this command is to /var/lib/docker create a temporary file in the host directory and link it to the directory in the container. /tmp
• ADD, copy files and rename
• EntryPoint, in order to shorten the boot time of Tomcat, the added java.security.egd system attribute points to the /dev/urandom entrypoint

This is done by adding Docker dependencies to the Spring Boot project.

Build a packaged environment

We need a Docker environment to package the Spring Boot project, and it's a hassle to build a docker environment in Windows, so here's the Centos 7 example.

Installing the Docker Environment

Installation

yum install docker

After the installation is complete, use the following command to start the Docker service and set it to boot:

ervice docker startchkconfig docker on#LCTT 译注：此处采用了旧式的 sysv 语法，如采用CentOS 7中支持的新式 systemd 语法，如下：systemctl  start docker.servicesystemctl  enable docker.service

Using the Docker China accelerator

vi  /etc/docker/daemon.json#添加后：{    "registry-mirrors": ["https://registry.docker-cn.com"],    "live-restore": true}

Restart Docker

systemctl restart docker

Input docker version return version information is installed properly.

Installing the JDK

yum -y install java-1.8.0-openjdk*

Configuring Environment variables
Open itvim /etc/profile
Add a bit of content

After the modification is complete, make it effective

source /etc/profile

Input java -version return version information is installed properly.

Installing MAVEN

Download:http://mirrors.shu.edu.cn/apache/maven/maven-3/3.5.2/binaries/apache-maven-3.5.2-bin.tar.gz

## 解压tar vxf apache-maven-3.5.2-bin.tar.gz## 移动mv apache-maven-3.5.2 /usr/local/maven3

Modify the environment variables to /etc/profile add the following lines in

MAVEN_HOME=/usr/local/maven3export MAVEN_HOMEexport PATH=${PATH}:${MAVEN_HOME}/bin

Remember to perform source /etc/profile the environment variables in effect.

Input mvn -version return version information is installed properly.

The entire build environment is configured to complete.

Deploying the Spring Boot project using Docker

On the project spring-boot-docker copy server, go to the project path to package the test.

#打包mvn package#启动java -jar target/spring-boot-docker-1.0.jar

Seeing the boot log for Spring boot indicates that the environment is not in trouble, we then use DockerFile to build the image.

mvn package docker:build

The first build may be a bit slow, and when you see the following, it shows that the build was successful:

...Step 1 : FROM openjdk:8-jdk-alpine ---> 224765a6bdbeStep 2 : VOLUME /tmp ---> Using cache ---> b4e86cc8654eStep 3 : ADD spring-boot-docker-1.0.jar app.jar ---> a20fe75963abRemoving intermediate container 593ee5e1ea51Step 4 : ENTRYPOINT java -Djava.security.egd=file:/dev/./urandom -jar /app.jar ---> Running in 85d558a10cd4 ---> 7102f08b5e95Removing intermediate container 85d558a10cd4Successfully built 7102f08b5e95[INFO] Built springboot/spring-boot-docker[INFO] ------------------------------------------------------------------------[INFO] BUILD SUCCESS[INFO] ------------------------------------------------------------------------[INFO] Total time: 54.346 s[INFO] Finished at: 2018-03-13T16:20:15+08:00[INFO] Final Memory: 42M/182M[INFO] ------------------------------------------------------------------------

Use docker images the commands to view the built-in mirrors:

docker imagesREPOSITORY                      TAG                 IMAGE ID            CREATED             SIZEspringboot/spring-boot-docker   latest              99ce9468da74        6 seconds ago       117.5 MB

springboot/spring-boot-dockerIs the image we built, the next step is to run the image

docker run -p 8080:8080 -t springboot/spring-boot-docker

After the boot is complete we use docker ps to view the running image:

docker psCONTAINER ID        IMAGE                           COMMAND                  CREATED             STATUS              PORTS                    NAMES049570da86a9        springboot/spring-boot-docker   "java -Djava.security"   30 seconds ago      Up 27 seconds       0.0.0.0:8080->8080/tcp   determined_mahavira

You can see that the container we are building is running, accessing the browser: http://192.168.0.x:8080/ , returning

Hello Docker!

Description successful using Docker to deploy Spring Boot project!

Sample Code-github

Sample code-Cloud Code

Reference

Spring Boot with Docker
Docker:spring Boot app released to Docker

Spring Boot 2.0 (iv): Deploy Spring boot with Docker