kubernetes-pause
FIPS 140-3Operating systemkubernetes-pause is the minimal Kubernetes infrastructure container used to hold a pod's shared namespaces.
kubernetes-pause is the minimal Kubernetes infrastructure container used to hold a pod's shared namespaces.
Pull the latest version of this image from the Ghost registry. Pulling requires authentication — generate a token and run docker login first (see Authentication below).
The Ghost catalog is public to browse, but pulling images requires an account. Generate a pull token below (or from your Account → Tokens page) — you'll get a ready-to-paste docker login command, then docker pull works.
The username is generated automatically (it looks like robot$<project>+<auto-id>, not the name you typed) and is included in the docker login command above. The secret is shown only once when you create the token.
All Ghost images are signed with cosign. Verifying the signature before deployment ensures the image has not been tampered with.
Install cosign via brew install cosign or download from the Sigstore releases page.
Reference this image in your Dockerfile as a base layer:
This is a vendor-built FIPS-enabled image: its cryptography runs on FIPS 140-3 validated modules configured by the upstream vendor. You can inspect the image metadata:
| Standard | FIPS 140-3 |
| Crypto module | Vendor-configured validated modules |
| Cryptography | Validated modules only |
| Use case | Government, regulated industries, compliance workloads |
All examples in this guide use the public image. If you've mirrored the repository for your own use, update the commands to reference your mirrored image instead.
For the examples, replace <tag> with the image tag you want to run. Common choices are 3, 3-dev, 3-fips, and
3-fips-dev.
For more background on how Kubernetes uses the upstream pause image, see
the upstream Kubernetes pause source tree.
The kubernetes-pause image is primarily intended for Kubernetes and other container runtimes that need a tiny
container to hold a namespace open. It is not typically run directly by end users, but you can start it locally to
verify behavior:
$ docker run --rm -d --name kubernetes-pause-test registry.ghost-prod.alphabravo.io/ghost-base/kubernetes-pause:<tag>
The upstream binary supports , which prints the embedded version and exits:
pause-v$ docker run --rm registry.ghost-prod.alphabravo.io/ghost-base/kubernetes-pause:<tag> -v
When you're done testing the image, stop and remove the container:
$ docker rm -f kubernetes-pause-test
| Feature | Upstream pause image | Docker Hardened kubernetes-pause |
|---|---|---|
| Runtime content | Minimal static binary | Minimal hardened runtime content |
| User | Non-root numeric user | Non-root numeric user |
| Shell access | No shell | No shell |
| Package manager | No package manager | No package manager |
| Metadata | Standard upstream image metadata | Hardened image metadata, SBOM, and VEX |
Ghost hardened images prioritize minimal runtime content to reduce attack surface. The runtime image doesn't contain a shell or package manager. Use Docker Debug when you need to inspect a running container.
If you need an interactive shell or package manager for local inspection, use a dev variant and override the entrypoint
to bash:
$ docker run --rm --entrypoint bash registry.ghost-prod.alphabravo.io/ghost-base/kubernetes-pause:3-dev -lc 'apt-get --version && locale'
The same pattern works for the FIPS-enabled dev image:
$ docker run --rm --entrypoint bash registry.ghost-prod.alphabravo.io/ghost-base/kubernetes-pause:3-fips-dev -lc 'apt-get --version && locale'
kubernetes-pause is a special-purpose infrastructure container, so migration usually means updating the image
reference used by your Kubernetes distribution, sandbox configuration, or local test environment rather than using it as
a general application base image.
/pause entrypoint for runtime use.dev or fips-dev only when you need interactive inspection or debugging, and pair them with --entrypoint bash
if you want a shell.-fips or -fips-dev tag.Ghost hardened images come in different variants depending on their intended use. Image variants are identified by their tag.
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:
Build-time variants typically include dev in the tag name and are intended for use in the first stage of a
multi-stage Dockerfile. These images typically:
FIPS variants include fips in the variant name and tag. They come in both runtime and build-time variants. These
variants use cryptographic modules that have been validated under FIPS 140, a U.S. government standard for secure
cryptographic operations. For example, usage of MD5 fails in FIPS variants.
To view the image variants and get more information about them, select the Tags tab for this repository, and then select a tag.
To migrate your application to a Ghost hardened image, you must update your Dockerfile. At minimum, you must update the base image in your existing Dockerfile to a Ghost hardened image. This and a few other common changes are listed in the following table of migration notes.
| Item | Migration note |
|---|---|
| Base image | Replace your base images in your Dockerfile with a Ghost hardened image. |
| Package management | Non-dev images, intended for runtime, don't contain package managers. Use package managers only in images with a dev tag. |
| Non-root user | By default, non-dev images, intended for runtime, run as the nonroot user. Ensure that necessary files and directories are accessible to the nonroot user. |
| Multi-stage build | Utilize images with a dev tag for build stages and non-dev images for runtime. For binary executables, use a static image for runtime. |
| TLS certificates | Ghost hardened images contain standard TLS certificates by default. There is no need to install TLS certificates. |
| 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. |
| Entry point | Ghost hardened images may have different entry points than images such as Docker Official Images. Inspect entry points for Ghost hardened images and update your Dockerfile if necessary. |
| No shell | By default, non-dev images, intended for runtime, don't contain a shell. Use dev images in build stages to run shell commands and then copy artifacts to the runtime stage. |
The following steps outline the general migration process.
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.
Update the base image in your Dockerfile.
Update the base image in your application's Dockerfile to the hardened image you found in the previous step. For
framework images, this is typically going to be an image tagged as dev because it has the tools needed to install
packages and dependencies.
For multi-stage Dockerfiles, update the runtime image in your Dockerfile.
To ensure that your final image is as minimal as possible, you should use a multi-stage build. All stages in your
Dockerfile should use a hardened image. While intermediary stages will typically use images tagged as dev, your
final runtime stage should use a non-dev image variant.
Install additional packages
Ghost hardened images contain minimal packages in order to reduce the potential attack surface. You may need to install additional packages in your Dockerfile. Inspect the image variants to identify which packages are already installed.
Only images tagged as dev typically have package managers. You should use a multi-stage Dockerfile to install the
packages. Install the packages in the build stage that uses a dev image. Then, if needed, copy any necessary
artifacts to the runtime stage that uses a non-dev image.
For Alpine-based images, you can use apk to install packages. For Debian-based images, you can use apt-get to
install packages.
The following are common issues that you may encounter during migration.
The hardened images intended for runtime don't contain a shell nor any tools for debugging. The recommended method for debugging applications built with Ghost 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.
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.
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.
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.
Ghost hardened images may have different entry points than images such as Docker Official Images. Use docker inspect
to inspect entry points for Ghost hardened images and update your Dockerfile if necessary.