A simple quick guide to deploy Spring Boot Application in Docker using docker and docker-compose. You can consider this same guide to Deploy a simple Spring Boot microservice in Docker.
1. Deploy Spring Boot Application in Docker
We Just need to do following simple steps to deploy your Spring Boot app in docker.
Step 1 : Create a simple Spring Boot app or download it from our git repository SpringBoot Helloworld
Step 2 : Create a Dockerfile in root directory of your application, and add commands to build docker image.
Step 3 : Create Docker image for your Spring Boot application and start container using docker or docker-compose commands.
1.1. Spring Boot Application
Let’s have a look into following example, which is a basic Spring boot microservice application.
Project Structure :
application.properties :
Application starts in port 8181 with /helloworld context path.
server.port=8181 server.servlet.context-path=/helloworld
HelloController :
A simple REST controller that mapped to GET request path /hello and it returns a simple message.
@RestController
public class HelloController {
@GetMapping("hello")
public String sayHello() {
return "Hello Developer, you are awesome!";
}
}
1.2. Create Dockerfile
To deploy an application in docker we need to build a docker-image first. Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image. In simple, Dockerfile is a text configuration file and it contains instructions to build docker-image. Following Dockerfile illustrates the instructions to build a simple Spring Boot Application.
#FROM java:8 FROM adoptopenjdk/openjdk11:alpine-jre LABEL maintainer="[email protected]" WORKDIR /myapp COPY target/spring-boot-docker-example-0.0.1-SNAPSHOT.jar /myapp/my-app.jar ENTRYPOINT ["java","-jar","my-app.jar"]
FROM : Instruction to specify a parent or base image from which you are building. In our case we need Java Runtime Environment to start our Spring Boot Application. We are using adoptopenjdk/openjdk11:alpine-jre as base image. Docker get it from Docker Hub which is a official repository for public docker images.
LABEL : Label is just to specify developer or organization information or url or email to represent whom it belongs.
WORKDIR : Instruction to specify working directory. This directory will be created in the container and run the specified commands from this directory.
COPY : Instruction to copy files from local source to container target.
ENTRYPOINT : Instruction to run specified commands once image successfully deployed and container is booted up.
1.3. Create Docker Image and run Container for Spring Boot App
A Docker image is a binary that includes all of the requirements for running a single Docker container, as well as metadata describing its needs and capabilities. You can think of it as a packaging technology.
Docker container is a lightweight, standalone, executable package of software that includes everything needed to run an application: code, runtime, system tools, system libraries and settings.
There are several ways to create docker image, Let’s have a look into how to create docker images using docker and docker-compose commands. Select the “Deploy Using Docker-Compose” from the following tabs if you would like to see deployment steps for using docker-compose.
1.3.1. Navigate to application root directory and run command docker build -t image-name:tag . , observe the dot at end of command, if you missed it you will get error.
$ docker build -t spring-boot-image:1.0 . Sending build context to Docker daemon 17.7MB Step 1/5 : FROM adoptopenjdk/openjdk11:alpine-jre ---> aa00f19e5b22 Step 2/5 : LABEL maintainer="[email protected]" ---> Using cache ---> 47702e062067 Step 3/5 : WORKDIR /myapp ---> Using cache ---> b90566ce5c6d Step 4/5 : COPY target/spring-boot-docker-example-0.0.1-SNAPSHOT.jar /myapp/my-app.jar ---> Using cache ---> b0c2fd9d66c0 Step 5/5 : ENTRYPOINT ["java","-jar","my-app.jar"] ---> Using cache ---> 39253544ef45 Successfully built 39253544ef45 Successfully tagged spring-boot-image:1.0
Verify Created images using $ docker images command :
$ docker images REPOSITORY TAG IMAGE ID CREATED SIZE spring-boot-image 1.0 39253544ef45 6 minutes ago 166MB adoptopenjdk/openjdk11 alpine-jre aa00f19e5b22 3 weeks ago 149MB
1.2.2. Now, our spring-boot-image is ready. we need to create and run a container using it. run command
$ docker run --name <container-name> -p <host-port:container-port> -t <image-name:tag>
$ docker run --name spring-boot-container -p 8080:8181 -t spring-boot-image:1.0 . ____ _ __ _ _ /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ \\/ ___)| |_)| | | | | || (_| | ) ) ) ) ' |____| .__|_| |_|_| |_\__, | / / / / =========|_|==============|___/=/_/_/_/ :: Spring Boot :: (v2.2.2.RELEASE) 2020-05-27 11:22:27.385 INFO 1 --- [ main] c.j.d.SpringBootHelloWorldApplication : Starting SpringBootHelloWorldApplication v0.0.1-SNAPSHOT on 5a5873dc878a with PID 1 (/myapp/my-app.jar started by root in /myapp) 2020-05-27 11:22:27.400 INFO 1 --- [ main] c.j.d.SpringBootHelloWorldApplication : No active profile set, falling back to default profiles: default 2020-05-27 11:22:30.925 INFO 1 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8181 (http) 2020-05-27 11:22:30.984 INFO 1 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat] 2020-05-27 11:22:30.988 INFO 1 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.29] 2020-05-27 11:22:31.343 INFO 1 --- [ main] o.a.c.c.C.[.[localhost].[/helloworld] : Initializing Spring embedded WebApplicationContext 2020-05-27 11:22:31.364 INFO 1 --- [ main] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 3590 ms 2020-05-27 11:22:33.217 INFO 1 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor' 2020-05-27 11:22:34.228 INFO 1 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8181 (http) with context path '/helloworld' 2020-05-27 11:22:34.273 INFO 1 --- [ main] c.j.d.SpringBootHelloWorldApplication : Started SpringBootHelloWorldApplication in 8.556 seconds (JVM running for 9.996)
Make sure you already installed Docker Compose in your environment.
1.3.1. Docker Compose is a tool that provides a way to orchestrate multiple containers that work together. For example you have multiple applications, rest-api, web-application and database … etc. We nee to run multiple docker containers such scenarios. we can use Docker Compose for defining and running multi-container Docker applications.
We need create a docker-compose.yml file in the root directory of application like following. The configuration properties are self explanatory.
version: '3'
services:
spring-boot-docker-app:
image: spring-boot-docker-image
build:
context: ./
dockerfile: Dockerfile
ports:
- 8080:8181
volumes:
- /storage/my-app
1.3.2. Once you created docker-compose.yml file run command $ docker-compose up
$ docker-compose up Creating network "spring-boot-docker-example_default" with the default driver Building spring-boot-docker-app Step 1/5 : FROM adoptopenjdk/openjdk11:alpine-jre alpine-jre: Pulling from adoptopenjdk/openjdk11 cbdbe7a5bc2a: Pull complete 525f2e30780d: Pull complete 29bfc0a3c5fd: Pull complete Digest: sha256:f92b946306c1f17be5578a84f61482766c4a47d6c75a2b49a49b7ef321cc750f Status: Downloaded newer image for adoptopenjdk/openjdk11:alpine-jre ---> aa00f19e5b22 Step 2/5 : LABEL maintainer="[email protected]" ---> Running in 710b85a52743 Removing intermediate container 710b85a52743 ---> 246aa42d0219 Step 3/5 : WORKDIR /myapp ---> Running in 7e0a3ed07870 Removing intermediate container 7e0a3ed07870 ---> d732b42efffa Step 4/5 : COPY target/spring-boot-docker-example-0.0.1-SNAPSHOT.jar /myapp/my-app.jar ---> ceaaed6ffa5a Step 5/5 : ENTRYPOINT ["java","-jar","my-app.jar"] ---> Running in 4fa0a0954493 Removing intermediate container 4fa0a0954493 ---> 66fc515e4bd9 Successfully built 66fc515e4bd9 Successfully tagged spring-boot-docker-image:latest WARNING: Image for service spring-boot-docker-app was built because it did not already exist. To rebuild this image you must use `docker-compose build` or `docker-compose up --build`. Creating spring-boot-docker-example_spring-boot-docker-app_1 ... done Attaching to spring-boot-docker-example_spring-boot-docker-app_1 spring-boot-docker-app_1 | spring-boot-docker-app_1 | . ____ _ __ _ _ spring-boot-docker-app_1 | /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ spring-boot-docker-app_1 | ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ spring-boot-docker-app_1 | \\/ ___)| |_)| | | | | || (_| | ) ) ) ) spring-boot-docker-app_1 | ' |____| .__|_| |_|_| |_\__, | / / / / spring-boot-docker-app_1 | =========|_|==============|___/=/_/_/_/ spring-boot-docker-app_1 | :: Spring Boot :: (v2.2.2.RELEASE) spring-boot-docker-app_1 | spring-boot-docker-app_1 | 2020-05-27 11:53:52.186 INFO 1 --- [ main] c.j.d.SpringBootHelloWorldApplication : Starting SpringBootHelloWorldApplication v0.0.1-SNAPSHOT on c8c8addb7d62 with PID 1 (/myapp/my-app.jar started by root in /myapp) spring-boot-docker-app_1 | 2020-05-27 11:53:52.204 INFO 1 --- [ main] c.j.d.SpringBootHelloWorldApplication : No active profile set, falling back to default profiles: default spring-boot-docker-app_1 | 2020-05-27 11:53:55.806 INFO 1 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8181 (http) spring-boot-docker-app_1 | 2020-05-27 11:53:55.848 INFO 1 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat] spring-boot-docker-app_1 | 2020-05-27 11:53:55.878 INFO 1 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.29] spring-boot-docker-app_1 | 2020-05-27 11:53:56.211 INFO 1 --- [ main] o.a.c.c.C.[.[localhost].[/helloworld] : Initializing Spring embedded WebApplicationContext spring-boot-docker-app_1 | 2020-05-27 11:53:56.211 INFO 1 --- [ main] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 3594 ms spring-boot-docker-app_1 | 2020-05-27 11:53:58.226 INFO 1 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor' spring-boot-docker-app_1 | 2020-05-27 11:53:59.140 INFO 1 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8181 (http) with context path '/helloworld' spring-boot-docker-app_1 | 2020-05-27 11:53:59.151 INFO 1 --- [ main] c.j.d.SpringBootHelloWorldApplication : Started SpringBootHelloWorldApplication in 8.588 seconds (JVM running for 10.15)
That’s all, your application will be started.
1.3.3. Some useful docker commands :
docker-compose up --build -d– If you have updated Dockerfile or .yml, to rebuild and run your containers. Use option-dto run docker container in detached mode.docker-compose stop– To stop all running containers.docker-compose start– To start all of your inactive containers.docker ps -aordocker-compose ps -a– To list all of docker containers.docker imagesordocker-compose images– To List all of docker images.docker history <image-name>– To see layered view of docker image how it build.docker logs <image-name>ordocker-compose logs <image-name>to see logs of your application
2. Test the application
Enter url in browser http://localhost:8181/helloworld/hello . On successful run of Spring Boot Application you will get following screen.
3. Conclusion
In this tutorial we walked through a simple Spring Boot example and we have covered a simple quick guide to deploy Spring Boot Application in Docker using docker and docker-compose commands, also you can consider this guide to deploy Spring Boot microservice in Docker.
You can checkout source code from our github repository.
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