How to use this image

All examples in this guide use the public image. If you’ve mirrored the repository for your own use (for example, to your Docker Hub namespace), update your commands to reference the mirrored image instead of the public one.

For example:

• Public image: dhi.io/<repository>:<tag>
• Mirrored image: <your-namespace>/dhi-<repository>:<tag>

For the examples, you must first use docker login dhi.io to authenticate to the registry to pull the images.

What's included in this Kyverno Reporter Policy Hardened image

This image contains kyverno-policy-reporter-ui, a Kyverno component that adds a web based UI for the Kyverno Policy Reporter component.

Start a kyverno-policy-reporter-ui instance

Run the following command and replace <tag> with the image variant you want to run.

Note:kyverno-policy-reporter-ui is primarily designed to run within a Kubernetes cluster as part of the complete Kyverno Policy Reporter deployment. The following standalone Docker command displays the available configuration options.

docker run -d --name kyverno-policy-reporter-ui -p 8080:8080 dhi.io/kyverno-policy-reporter-ui:<tag> run

Common kyverno-policy-reporter-ui use cases

Install Kyverno Policy Reporter using Helm

You can install Kyverno Policy Reporter using the official helm chart and replace the image. Replace <your-registry-secret> with your Kubernetes image pull secret⁠ and <tag> with the desired image tag.

helm repo add policy-reporter https://kyverno.github.io/policy-reporter
helm repo update

helm upgrade --install policy-reporter policy-reporter/policy-reporter \
  --create-namespace -n policy-reporter \
  --set metrics.enabled=true \
  --set api.enabled=true \
  --set ui.enabled=true \
  --set "images.pullSecrets[0].name=<your-registry-secret>" \
  --set image.registry=dhi.io \
  --set image.repository=kyverno-policy-reporter \
  --set image.tag=<tag> \
  --set ui.image.registry=dhi.io \
  --set ui.image.repository=kyverno-policy-reporter-ui \
  --set ui.image.tag=<tag> \

Access Policy Reporter UI

Access the Policy Reporter UI at http://localhost:8080⁠ via kubectl port forward:

kubectl port-forward service/policy-reporter-ui 8080:8080 -n policy-reporter

Non-hardened images vs Docker Hardened Images

Key differences

Why no shell or package manager?

Docker Hardened Images prioritize security through minimalism:

• Reduced attack surface: Fewer binaries mean fewer potential vulnerabilities
• Immutable infrastructure: Runtime containers shouldn't be modified after deployment
• Compliance ready: Meets strict security requirements for regulated environments

Hardened image debugging

The hardened images intended for runtime don't contain a shell nor any tools for debugging. Common debugging methods for applications built with Docker Hardened Images include:

• Docker Debug⁠ to attach to containers
• Docker's Image Mount feature to mount debugging tools
• Ecosystem-specific debugging approaches

Docker Debug provides a shell, common debugging tools, and lets you install other tools in an ephemeral, writable layer that only exists during the debugging session.

For example, you can use Docker Debug:

docker debug dhi-kyverno-policy-reporter-ui

or mount debugging tools with the Image Mount feature:

docker run --rm -it --pid container:my-container \
  --entrypoint /dbg/bin/sh \
  --mount=type=image,source=dhi.io/busybox:1,destination=/dbg,ro \
  dhi.io/kyverno-policy-reporter-ui:<tag>

CLI differences from upstream

The Docker Hardened Image uses a cobra-style CLI with subcommands, while the upstream image uses a traditional flag-based CLI. This is an important difference to be aware of when migrating.

Upstream behavior:

• Binary starts the server by default when run without arguments
• Configuration is done via command-line flags (e.g., -port, -config)

DHI behavior:

• Binary requires the run subcommand to start the server
• Running without arguments displays help and exits
• Configuration is done via flags to the run subcommand (e.g., run --port, run --config)

Migration impact:

All docker run commands and Kubernetes container specs must include the run subcommand:

# Upstream command
docker run ghcr.io/kyverno/policy-reporter-ui:latest

# DHI equivalent - requires "run" subcommand
docker run dhi.io/kyverno-policy-reporter-ui:<tag> run

For Kubernetes deployments, update your container args:

containers:
  - name: policy-reporter-ui
    image: dhi.io/kyverno-policy-reporter-ui:<tag>
    args:
      - run
      # Add any additional flags here

Image variants

Docker Hardened Images come in different variants depending on their intended use.

• Runtime variants are designed to run your application in production. These images are intended to be used either directly or as the FROM image in the final stage of a multi-stage build. These images typically:

  • Run as the nonroot user
  • Do not include a shell or a package manager
  • Contain only the minimal set of libraries needed to run the app

• Build-time variants typically include dev in the variant name and are intended for use in the first stage of a multi-stage Dockerfile. These images typically:

  • Run as the root user
  • Include a shell and package manager
  • Are used to build or compile applications

Migrate to a Docker Hardened Image

To migrate your application to a Docker Hardened Image, you must update your Kubernetes manifests or Docker configurations. At minimum, you must update the base image in your existing deployment to a Docker Hardened Image. This and a few other common changes are listed in the following table of migration notes.

The following steps outline the general migration process.

1. Find hardened images for your app.

   A hardened image may have several variants. Inspect the image tags and find the image variant that meets your needs. Remember that Kyverno requires multiple components to function properly.

2. Update your image references in your Kubernetes manifests.

   Update the image references in your Kyverno deployment manifests to use the hardened images. If using Helm, update your values file accordingly:

   • From: ghcr.io/kyverno/policy-reporter-ui:<tag>
   • To: dhi.io/kyverno-policy-reporter-ui:<tag>

3. For custom deployments, update the runtime image in your Dockerfile.

   If you're building custom images based on kyverno-policy-reporter-ui, ensure that your final image uses the hardened kyverno-policy-reporter-ui as the base. For multi-stage builds, use images tagged as dev for build stages and non-dev images for runtime.

4. Verify component compatibility.

   Check if your manifests include command: or args: overrides and ensure they align with the hardened image defaults.

5. Test policy scanning and reporting.

   After migration, verify that UI continues to be accessible and responsive.

Troubleshoot migration

The following are common issues that you may encounter during migration.

General debugging

The hardened images intended for runtime don't contain a shell nor any tools for debugging. The recommended method for debugging applications built with Docker Hardened Images is to use Docker Debug⁠ to attach to these containers. Docker Debug provides a shell, common debugging tools, and lets you install other tools in an ephemeral, writable layer that only exists during the debugging session.

Permissions

By default image variants intended for runtime, run as the nonroot user. Ensure that necessary files and directories are accessible to the nonroot user. You may need to copy files to different directories or change permissions so your application running as the nonroot user can access them.

Privileged ports

Non-dev hardened images run as a nonroot user by default. As a result, applications in these images can't bind to privileged ports (below 1024) when running in Kubernetes or in Docker Engine versions older than 20.10.

No shell

By default, image variants intended for runtime don't contain a shell. Use dev images in build stages to run shell commands and then copy any necessary artifacts into the runtime stage. In addition, use Docker Debug to debug containers with no shell.

Entry point

Docker Hardened Images may have different entry points than images such as Docker Official Images. Use docker inspect to inspect entry points for Docker Hardened Images and update your Dockerfile if necessary.