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 Reports Controller Hardened image

This image contains kyverno-reports-controller, a Kyverno component that generates and manages PolicyReports and EphemeralReports for compliance and observability. The entry point for the image is kyverno-reports-controller which provides background policy scanning and compliance evaluation, PolicyReports and EphemeralReports generation, continuous monitoring and violation tracking, and metrics and event generation for observability.

Start a kyverno-reports-controller instance

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

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

docker run --rm -it dhi.io/kyverno-reports-controller:<tag> --help

Common kyverno-reports-controller use cases

Generate compliance and policy violation reports

kyverno-reports-controller requires write access to create PolicyReports, ClusterPolicyReports, and EphemeralReports. These reports help track policy violations and maintain security compliance.

The following example shows a basic PolicyReport generated by the controller:

apiVersion: wgpolicyk8s.io/v1alpha2
kind: PolicyReport
metadata:
  name: policy-report-ns-default
  namespace: default
summary:
  pass: 1
results:
  - policy: require-pod-security-standards
    rule: check-security-context
    result: pass
    scored: true

Deploy kyverno-reports-controller in Kubernetes

First follow the authentication instructions for DHI in Kubernetes⁠.

The controller is typically deployed as part of a complete Kyverno installation in Kubernetes.

The following example shows a Deployment configuration for kyverno-reports-controller:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: kyverno-reports-controller
  namespace: kyverno
spec:
  template:
    spec:
      containers:
      - name: kyverno-reports-controller
        image: dhi.io/kyverno-reports-controller:<tag>
        args:
        - --metrics-bind-addr=:8000
        - --leader-elect
        ports:
        - containerPort: 8000
          name: metrics
      imagePullSecrets:
      - name: <secret name>

Monitor policy compliance with metrics

kyverno-reports-controller provides metrics endpoints for monitoring policy compliance and controller health. These metrics can be scraped by Prometheus or other monitoring systems to provide visibility into policy violations and compliance trends.

Install Kyverno using Helm

You can install Kyverno 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 kyverno https://kyverno.github.io/kyverno
helm repo update

helm upgrade --install kyverno kyverno/kyverno \
  -n kyverno --create-namespace --wait \
  --set "images.pullSecrets[0].name=<your-registry-secret>" \
  --set image.registry=dhi.io \
  --set reportsController.image.repository=kyverno-reports-controller \
  --set reportsController.image.tag=<tag> \
  --set reportsController.podSecurityContext.runAsUser=65532

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-reports-controller

or mount debugging tools with the Image Mount feature:

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

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: bitnami/kyverno-reports-controller:<tag>
   • To: dhi.io/kyverno-reports-controller:<tag>

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

   If you're building custom images based on kyverno-reports-controller, ensure that your final image uses the hardened kyverno-reports-controller 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.

   Ensure all Kyverno components (main controller, reports-controller, cleanup-controller) are using compatible versions. The reports-controller works in conjunction with these other components. 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 policy evaluation, report generation, and metrics collection continue to function correctly with the hardened image. Confirm that PolicyReports and EphemeralReports are created as expected, and that the /metrics endpoint is scraping correctly.

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.

kyverno-reports-controller requires write access to create PolicyReports, ClusterPolicyReports, and EphemeralReports in the cluster. Ensure your RBAC configuration grants appropriate permissions.

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.