Chainguard Container for maven

Minimal image with the Maven build system.

Chainguard Containers are regularly-updated, secure-by-default container images.

Download this Container Image

For those with access, this container image is available on cgr.dev:

docker pull cgr.dev/ORGANIZATION/maven:latest

Be sure to replace the ORGANIZATION placeholder with the name used for your organization's private repository within the Chainguard Registry.

Compatibility Notes

The Maven Chainguard image was built to work as a drop-in replacement for the official Maven image on Docker Hub. Like most of Chainguard's images, the Maven image does not operate as the root user and includes only the minimum packages needed to function.

Chainguard Maven images come with different versions of OpenJDK. This means you will need to ensure that you choose the correct image tag for your application needs.

Getting Started

To illustrate how you can use Chainguard's Maven image, you will need a Java application for the Maven image to build. This overview will use a Spring Boot example application found in this GitHub repository.

Clone the repository to your local machine and navigate into the project directory:

git clone https://github.com/chainguard-dev/learning-labs-java.git
cd learning-labs-java/

The example's Dockerfile uses the default Maven image from Docker Hub. Overwrite this file with the following command to instead use the Chainguard Maven Image:

cat > Dockerfile <<EOF
FROM cgr.dev/chainguard/maven

WORKDIR /work

COPY src/ src/
COPY pom.xml pom.xml

RUN mvn clean package
RUN REPOSITORY=$(mvn help:evaluate -Dexpression=settings.localRepository -q -DforceStdout) && rm -rf ${REPOSITORY}

WORKDIR /app

RUN cp /work/target/java-demo-app-1.0.0.jar .

ENTRYPOINT ["java", "-jar", "java-demo-app-1.0.0.jar"]
EOF

Then build an image using this Dockerfile with the following command:

docker build -t maven-app .

This command tags the image as maven-app. Run this image:

docker run --rm -p 8080:8080 maven-app

The app should now be running and you can interact with it by accessing it at localhost:8080/hello, either in your browser or with curl, as in the following example:

curl localhost:8080/hello

Hello, World! I love Chainguard!

This shows that the application is working as expected. You can stop the container by pressing CTRL + C in the terminal where it's running.

Using Chainguard's Maven image in a multi-stage build

‍ The image built in the previous example still includes build tooling and source code that aren't needed in the production image. Using a multi-stage build can reduce the number of dependencies.

To try this out, create a new Dockerfile named Dockerfile.multi-stage:

cat > Dockerfile.multi-stage <<EOF
FROM cgr.dev/chainguard/maven AS builder

WORKDIR /work

COPY src/ src/
COPY pom.xml pom.xml

RUN mvn clean package
RUN REPOSITORY=$(mvn help:evaluate -Dexpression=settings.localRepository -q -DforceStdout) && rm -rf ${REPOSITORY}

FROM cgr.dev/chainguard/jre AS runner

WORKDIR /app

COPY --from=builder /work/target/java-demo-app-1.0.0.jar .

ENTRYPOINT ["java", "-jar", "java-demo-app-1.0.0.jar"]
EOF

Note that there are two FROM lines, the first one creates the builder image much as before and the second (named runner) copies the built JAR from the builder step into the smaller cgr.dev/chainguard/jre image. The result is a container image that only contains the JRE and the built application.

Using this multi-stage Dockerfile, build a new image:

docker build -f Dockerfile.multi-stage -t maven-app-multi-stage .

This command tags the image as maven-app-multi-stage. Run this image:

docker run --rm -p 8080:8080 maven-app-multi-stage

Again, the application will be accessible at localhost:8080/hello:

curl localhost:8080/hello

Hello, World! I love Chainguard!

Once again, press CTRL + C to stop the running container.

Documentation and Resources

• Learning Lab: Chainguard's Java Container Image
• Chainguard Blog: Building minimal and low CVE images for Java
• Video: Building Minimal Images for Applications with Runtimes
• Video: How to Migrate a Java Application to Chainguard Images
• Vulnerability Comparison: maven
• Apache Maven Project Site

What are Chainguard Containers?

Chainguard's free tier of Starter container images are built with Wolfi, our minimal Linux undistro.

All other Chainguard Containers are built with Chainguard OS, Chainguard's minimal Linux operating system designed to produce container images that meet the requirements of a more secure software supply chain.

The main features of Chainguard Containers include:

• Minimal design, without unnecessary software bloat
• Daily builds to ensure container images are up-to-date with available security patches
• High quality build-time SBOMs attesting to the provenance of all artifacts within the image
• Verifiable signatures provided by Sigstore
• Reproducible builds with Cosign and apko (read more about reproducibility)

For cases where you need container images with shells and package managers to build or debug, most Chainguard Containers come paired with a development, or -dev, variant.

In all other cases, including Chainguard Containers tagged as :latest or with a specific version number, the container images include only an open-source application and its runtime dependencies. These minimal container images typically do not contain a shell or package manager.

Although the -dev container image variants have similar security features as their more minimal versions, they include additional software that is typically not necessary in production environments. We recommend using multi-stage builds to copy artifacts from the -dev variant into a more minimal production image.

Need additional packages?

To improve security, Chainguard Containers include only essential dependencies. Need more packages? Chainguard customers can use Custom Assembly to add packages, either through the Console, chainctl, or API.

To use Custom Assembly in the Chainguard Console: navigate to the image you'd like to customize in your Organization's list of images, and click on the Customize image button at the top of the page.

Learn More

Refer to our Chainguard Containers documentation on Chainguard Academy. Chainguard also offers VMs and Libraries — contact us for access.

Trademarks

This software listing is packaged by Chainguard. The trademarks set forth in this offering are owned by their respective companies, and use of them does not imply any affiliation, sponsorship, or endorsement by such companies.