Spring Boot 2.0 (iii): 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

   @SpringBootApplication public  Class dockerapplication {public static void main (string[]  Args) {springapplication. Run (dockerapplication. Classargs              /span>              

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-properties Add 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 Maven Plugin--<plugin><groupid>com.spotify</groupId><artifactid>docker-maven-plugin</artifactId><version>1.0.0</version><configuration><imagename>${docker.image.prefix}/${ Project.artifactid}</imagename><dockerdirectory>src/main/docker< Span class= "NT" ></dockerdirectory><resources><resource>< Span class= "NT" ><targetpath>/</targetpath><directory>${ Project.build.directory}</directory><include>${ Project.build.finalname}.jar</include></resource> </resources></configuration></plugin>< span class= "C" ><!--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

install docker

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

service 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

-y install java-1.8.0-openjdk*

Configure environment variables Open vim /etc/profile Add a bit of content

export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.161-0.b14.el7_4.x86_64 export PATH=$PATH:$JAVA_HOME/bin 

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 Span class= "NT" >---> 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

-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!

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