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Implementation method of deploying SpringBoot project with Docker

  • 2021-07-18 09:34:04
  • OfStack

The development of Docker technology provides a more convenient environment for micro-service landing. It is actually very simple to deploy Spring Boot with Docker. Let's learn this article briefly.

First build a simple Spring Boot project, then add Docker support to the project, and finally deploy the project.

1 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>

Creates an DockerController with an index () method that returns: Hello Docker! 


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

Startup class 


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

After adding, start the project. After starting successfully, the browser visits: http://localhost: 8080/, and the page returns: Hello Docker! The Spring Boot project is configured correctly.

Spring Boot project adds Docker support

Add Docker mirror name in pom. xml-properties 


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

Add the Docker build plug-in to 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</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 Dockerfile file under the directory src/main/docker, and the Dockerfile file is used to explain how to build the image. 


FROM openjdk:8-jdk-alpine
VOLUME /tmp
ADD spring-boot-docker-1.0.jar app.jar
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]

This Dockerfile file is very simple, build the basic environment of Jdk, add Spring Boot Jar to the image, and explain briefly 1:

FROM means using Jdk8 environment as the basic image. If the image is not local, it will be downloaded from DockerHub VOLUME and VOLUME point to the/tmp directory. Since Spring Boot uses the built-in Tomcat container, Tomcat defaults to/tmp as its working directory. The effect of this command is to create a temporary file in the/var/lib/docker directory of the host and link it to the/tmp directory in the container ADD, copy file and rename ENTRYPOINT, in order to shorten the startup time of Tomcat, add the system attribute of java. security. egd pointing to/dev/urandom as ENTRYPOINT

This completes the Spring Boot project adding the Docker dependency.

Building a Packaging Environment

We need to have an Docker environment to package the Spring Boot project. It is very troublesome to build an Docker environment in Windows, so I take Centos 7 as an example here.

Installing the Docker environment

Installation 


yum install docker

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


service docker start
chkconfig docker on
 
#LCTT  The old style is adopted here  sysv  Grammar, such as using CentOS 7 New styles supported in  systemd  Syntax, as follows: 
systemctl start docker.service
systemctl enable docker.service

Using Docker China Accelerator 


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

Restart docker 


<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>
0

Enter docker version to return version information and install normally.

Installing JDK 


<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>
1

Configure the environment variable to open vim/etc/profile Add 1 


<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>
2

After the modification is completed, make it effective 


source /etc/profile

Enter java-version to return version information and install normally.

Installing MAVEN

Download: http://mirrors.shu.edu.cn/apache/maven/maven-3/3.5. 2/binaries/apache-maven-3. 5.2-bin.tar.gz 


<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>
4

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


<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>
5

Remember to execute source/etc/profile to validate the environment variables.

Enter mvn-version to return version information and install normally.

In this way, the whole build environment is configured.

Deploying the Spring Boot project with Docker

Copy the project spring-boot-docker to the server, and enter the project path for packaging test. 


<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>
6

After seeing the startup log of Spring Boot, it shows that there is no problem with the environment configuration. Next, we use DockerFile to build the image. 


<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>
7

The first build may be a little slow, and it is a success when you see the following: 


...
Step 1 : FROM openjdk:8-jdk-alpine
 ---> 224765a6bdbe
Step 2 : VOLUME /tmp
 ---> Using cache
 ---> b4e86cc8654e
Step 3 : ADD spring-boot-docker-1.0.jar app.jar
 ---> a20fe75963ab
Removing intermediate container 593ee5e1ea51
Step 4 : ENTRYPOINT java -Djava.security.egd=file:/dev/./urandom -jar /app.jar
 ---> Running in 85d558a10cd4
 ---> 7102f08b5e95
Removing intermediate container 85d558a10cd4
Successfully 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 the docker images command to view the built image: 


<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>
9

springboot/spring-boot-docker is the image we built, and the next step is to run it 


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

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


docker ps
CONTAINER ID    IMAGE              COMMAND         CREATED       STATUS       PORTS          NAMES
049570da86a9    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 built is running, visit the browser: http://192.168. 0. x: 8080/, and return 


Hello Docker!

Explain the successful deployment of Spring Boot project using Docker!

Sample code: https://github.com/ityouknow/spring-boot-examples

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