Chainguard Container for rancher-hardened-kubernetes-compat-fips

FIPS-compliant Kubernetes components compatible with Rancher's RKE2

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/rancher-hardened-kubernetes-compat-fips:latest

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

Compatibility Notes

Chainguard's rancher-hardened-kubernetes-compat-fips container image is a drop-in replacement for the official rancher/hardened-kubernetes image.

This image contains FIPS-compliant Kubernetes control plane components:

• kube-apiserver
• kube-controller-manager
• kube-scheduler
• kube-proxy
• kubelet
• kubectl

All components are built with FIPS 140-2 validated cryptographic modules and are fully compatible with RKE2.

This image is designed to work with Chainguard's rke2-runtime images. When using preloaded images with RKE2, both the runtime and Kubernetes components must be tagged with the RKE2-compatible format: vX.Y.Z-rke2r<N>

FIPS Compliance

All Kubernetes components in this image are:

• Built with FIPS 140-2 validated cryptographic modules
• Compiled with FIPS-compliant OpenSSL (openssl-provider-fips)
• Configured to use FIPS mode by default

Getting Started

Using with RKE2 in Air-Gapped Environments

To deploy Chainguard's FIPS Kubernetes components with RKE2, you'll need to preload both the runtime and Kubernetes images.

RKE2 expects preloaded images to have reference tags in the following format: vX.Y.Z-rke2r1 Example Tags: Runtime: rke2-runtime:v1.33.5-rke2r1 Kubernetes: rancher/hardened-kubernetes:v1.33.5-rke2r1-build20250910

Step 1: Pull and Prepare Runtime Image

# Pull the runtime image
docker pull cgr.dev/ORGANIZATION/rke2-runtime:v1.33.5-rke2r1

# Tag it for RKE2
docker tag cgr.dev/ORGANIZATION/rke2-runtime:v1.33.5-rke2r1 rancher/rke2-runtime:v1.33.5-rke2r1

# Save it as a tar
docker save --output /tmp/rke2-runtime.tar rancher/rke2-runtime:v1.33.5-rke2r1

Step 2: Pull and Prepare Kubernetes Components Image

# Pull our FIPS K8s components image
docker pull cgr.dev/ORGANIZATION/rancher-hardened-kubernetes-compat-fips:v1.33.5-rke2r1

# Tag it with the upstream format RKE2 expects
docker tag cgr.dev/ORGANIZATION/rancher-hardened-kubernetes-compat-fips:v1.33.5-rke2r1 \
  rancher/hardened-kubernetes:v1.33.5-rke2r1-build20250910

# Save it as a tar
docker save --output /tmp/hardened-kubernetes.tar \
  rancher/hardened-kubernetes:v1.33.5-rke2r1-build20250910

Step 3: Deploy RKE2 with Preloaded Images

Place both tar files in the RKE2 agent images directory:

mkdir -p /var/lib/rancher/rke2/agent/images
cp /tmp/rke2-runtime.tar /var/lib/rancher/rke2/agent/images/
cp /tmp/hardened-kubernetes.tar /var/lib/rancher/rke2/agent/images/

Start RKE2:

docker run --rm --privileged \
  --network=host \
  --cgroupns=host \
  -v /var/lib/rancher/rke2:/var/lib/rancher/rke2 \
  cgr.dev/ORGANIZATION/rke2-runtime-airgap:latest server \
  --token=test \
  --runtime-image="rancher/rke2-runtime:v1.33.5-rke2r1"

RKE2 will automatically import and use your FIPS-compliant Kubernetes components.

Docker Testing

For quick validation, you can test individual Kubernetes binaries:

# Test kube-apiserver
docker run --rm cgr.dev/ORGANIZATION/rancher-hardened-kubernetes-compat-fips:latest \
  kube-apiserver --help

Documentation and Resources

For more information on working with RKE2 and Kubernetes components, please refer to:

• RKE2 Official Documentation
• Rancher Hardened Kubernetes GitHub

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.