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 virt-operator image

This Docker Hardened Virt Operator image is a component of the KubeVirt⁠ project.

• virt-operator: Virt Operator deploys and manages the KubeVirt virtualization infrastructure in Kubernetes

KubeVirt extends Kubernetes with virtualization capabilities. The virt-operator is one of several KubeVirt components typically deployed by the KubeVirt operator as part of a full installation.

Run the virt-operator container

The Virt Operator is designed to run within a Kubernetes cluster as part of the KubeVirt operator deployment.

To display help information:

docker run --rm dhi.io/virt-operator:<tag> --help

Deploy KubeVirt in Kubernetes

The recommended way to deploy KubeVirt (including virt-operator) is using the official KubeVirt operator manifests. Replace <tag> with the KubeVirt release that matches your image line (for example, v1.5.3 for 1.5.x images, v1.6.4 for 1.6.x images, or v1.7.2 for 1.7.x images).

1. Install the KubeVirt operator:

kubectl apply -f https://github.com/kubevirt/kubevirt/releases/download/<tag>/kubevirt-operator.yaml

1. Create the KubeVirt custom resource:

kubectl apply -f https://github.com/kubevirt/kubevirt/releases/download/<tag>/kubevirt-cr.yaml

1. Verify the deployment:

kubectl get pods -n kubevirt

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 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. These images typically:

  • Run as the root user
  • Include a shell and package manager

• FIPS variants include fips in the variant name and tag. They use cryptographic modules validated under FIPS 140.

Migrate to a Docker Hardened Image

To migrate your application to a Docker Hardened Image, you must update your Dockerfile. At minimum, you must update the base image in your existing Dockerfile to a Docker Hardened Image.

Troubleshooting 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. To avoid issues, configure your application to listen on port 1025 or higher inside the container, even if you map it to a lower port on the host. For example, docker run -p 80:8080 my-image will work because the port inside the container is 8080, and docker run -p 80:81 my-image won't work because the port inside the container is 81.

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.