Spring Boot Application Helm Chart Example

Build docker image (JVM)

Rename image in demoweb/docker-compose.yml.

build:
    context: .
image: binblee/springboot-helm-chart:jre-17

Build docker image use docker-compose command.

➜ cd demoweb
➜ docker compose build
➜ docker push xxxx

Unit test:

➜ cd demoweb
➜ docker compose up -d web

Visit http://localhost:8080/ you should get 'Hello World.'

Shut it down:

➜ docker compose down

If you prefer to use docker to build image:

➜ cd demoweb
➜ docker build -t xxxx .
➜ docker push xxxx

Build docker image (GraalVM)

Springboot 3.0 supports build native exectuable using GraalVM, we can leverage this feature to build a native executable docker image.

➜ cd demoweb
➜ docker compose build web-graalvm

demoweb/docker-compose.yml will tell you that native docker image is built with another Dockerfile: demoweb/Dockerfile.graalvm.

Also to be noted that a native plugin is added to demoweb/pom.xml

<plugin>
  <groupId>org.graalvm.buildtools</groupId>
  <artifactId>native-maven-plugin</artifactId>
</plugin>

You can up and run two images with one command:

➜ cd demoweb
➜ docker compose up -d

You should get two healthy containers:

NAME                    COMMAND                  SERVICE             STATUS              PORTS
demoweb-web-1           "sh -c 'java $JAVA_O…"   web                 running (healthy)   0.0.0.0:8080->8080/tcp
demoweb-web-graalvm-1   "/demoweb"               web-graalvm         running (healthy)   0.0.0.0:8888->8888/tcp

Test JVM version with http://localhost:8080, while GraalVM version with http://localhost:8888

Deploy using helm

Rename image image.repository and tag in demoweb/charts/springboot-demoweb/values.yaml with your image name and tag.

image:
  repository: binblee/springboot-helm-chart
  tag: graalvm-22.3-java17

You should have a running Kubernetes cluster and helm installed before proceed.

Deploy application using helm.

➜ cd demoweb/charts
➜ helm install demo ./springboot-demoweb/ 

Run port-forward and test it:

➜ kubectl port-forward service/demo-springboot-demoweb 8080:80
➜ curl http://localhost:8080

You should see "Hello World."

Uninstall demo application in cluster:

➜ helm uninstall demo

JVM image vs GraalVM image

We have two docker images now, one is build with JVM, the other one is build with graalvm native-image. Size of native exectuable image is about 1/3 of the classic JVM one. Quite impressive.

springboot-helm-chart:jre-17         294MB
springboot-helm-chart:graalvm-22.3   78.9MB

For more details, please refer to https://docs.spring.io/spring-boot/docs/current/reference/html/native-image.html#native-image