Chainguard Image for open-liberty

Open Liberty is a highly composable, fast to start, dynamic application server runtime environment.

Chainguard Images are regularly-updated, minimal container images with low-to-zero CVEs.

Download this Image

This image is available on cgr.dev:

docker pull cgr.dev/ORGANIZATION/open-liberty: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 Open Liberty Chainguard image was built to work as a drop-in replacement for the official openliberty/open-liberty image. This image supports the same environment variables as the openliberty/open-liberty image but also has a number of key differences, including the following:

• The GID for the default user is 1001 instead of 0
• Open Liberty is located in /usr/share/java/open-liberty instead of /opt/ol/wlp
• The runtime and buildtime helpers can be found in /usr/share/java/open-liberty/helpers instead of /opt/ol/helpers
• The class cache is located in /output/.classCache instead of /opt/java/.scc
• This image is Wolfi-based, unlike upstream, which leverages Ubuntu and UBI

Getting Started

To get started with Chainguard's Open Liberty image, derive an image containing your application.

Example Dockerfile:

FROM cgr.dev/ORGANIZATION/open-liberty:latest

COPY --chown=1001:1001 server.xml /config/server.xml
COPY --chown=1001:1001 path/to/application.jar /config/dropins/application.jar

RUN features.sh && configure.sh

Copy your application to the /config/dropins folder. Any artifacts placed here will be automatically deployed by Open Liberty. These artifacts can be updated, added, and removed without restarting the server.

The server manifest, server.xml, contains all of the features we may want to enable. Append any additional features your application leverages to the server manifest.

The features.sh script will leverage featureUtility to install any features defined in the server manifest. The configure.sh script will apply the server configuration, any iFixes in /fixes, and regenerate the class cache.

Documentation and Resources

• Official Open Liberty documentation.
• Official Open Liberty guides
• Build an application image with Open Liberty

Contact Support

If you have a Zendesk account (typically set up for you by your Customer Success Manager) you can reach out to Chainguard's Customer Success team through our Zendesk portal.

What are Chainguard Images?

Chainguard Images are a collection of container images designed for security and minimalism.

Many Chainguard Images are distroless; they contain only an open-source application and its runtime dependencies. These images do not even contain a shell or package manager. Chainguard Images are built with Wolfi, our Linux undistro designed to produce container images that meet the requirements of a secure software supply chain.

The main features of Chainguard Images include:

• Minimal design, with no unnecessary software bloat
• Automated nightly builds to ensure Images are completely up-to-date and contain all available security patches
• High quality build-time SBOMs (software bills of materials) attesting the provenance of all artifacts within the Image
• Verifiable signatures provided by Sigstore
• Reproducible builds with Cosign and apko (read more about reproducibility)

-dev Variants

As mentioned previously, Chainguard’s distroless Images have no shell or package manager by default. This is great for security, but sometimes you need these things, especially in builder images. For those cases, most (but not all) Chainguard Images come paired with a -dev variant which does include a shell and package manager.

Although the -dev image variants have similar security features as their distroless versions, such as complete SBOMs and signatures, they feature additional software that is typically not necessary in production environments. The general recommendation is to use the -dev variants only to build the application and then copy all application artifacts into a distroless image, which will result in a final container image that has a minimal attack surface and won’t allow package installations or logins.

That being said, it’s worth noting that -dev variants of Chainguard Images are completely fine to run in production environments. After all, the -dev variants are still more secure than many popular container images based on fully-featured operating systems such as Debian and Ubuntu since they carry less software, follow a more frequent patch cadence, and offer attestations for what they include.

Learn More

To better understand how to work with Chainguard Images, we encourage you to visit Chainguard Academy, our documentation and education platform.