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.

Start a Mimir instance

The Docker Hardened Mimir image requires a configuration file to start. Mimir has no built-in default configuration, so you must supply one via --config.file. The HTTP API and query frontend are served on port 8080; the gRPC listener is on port 9095.

Create a minimal configuration file for monolithic mode using local filesystem storage:

multitenancy_enabled: false

blocks_storage:
  backend: filesystem
  filesystem:
    dir: /var/mimir/blocks
  bucket_store:
    sync_dir: /var/mimir/tsdb-sync

alertmanager:
  data_dir: /var/mimir/alertmanager-data

compactor:
  data_dir: /var/mimir/compactor-data

ruler:
  rule_path: /var/mimir/ruler-data

alertmanager_storage:
  backend: filesystem
  filesystem:
    dir: /var/mimir/alertmanager

ruler_storage:
  backend: filesystem
  filesystem:
    dir: /var/mimir/ruler

ingester:
  ring:
    replication_factor: 1

Run Mimir in monolithic mode with the configuration above, replacing <tag> with the image variant you want to run:

$ docker run -d --name mimir \
  -v /path/to/mimir.yaml:/etc/mimir/config.yaml:ro \
  -v mimir_data:/var/mimir \
  -p 8080:8080 \
  dhi.io/mimir:<tag> \
  --config.file=/etc/mimir/config.yaml \
  --target=all

Verify Mimir is ready:

$ curl http://localhost:8080/ready
ready

Common Mimir use cases

Mount a configuration file

Mount your Mimir configuration file into the container at a path you reference with --config.file. Mimir supports YAML configuration files and also accepts configuration via environment variable overrides using the MIMIR_<SECTION>_<KEY> pattern.

$ docker run -d --name mimir \
  -v /path/to/mimir.yaml:/etc/mimir/config.yaml:ro \
  -p 8080:8080 \
  dhi.io/mimir:<tag> \
  --config.file=/etc/mimir/config.yaml \
  --target=all

Persist metric storage

Mimir stores block data, compactor state, and other persistent data on disk. The image pre-creates /var/mimir with ownership 65532:65532, which matches the nonroot user the container runs as. Mount a named volume to /var/mimir and no additional permission setup is required:

$ docker run -d --name mimir \
  -v /path/to/mimir.yaml:/etc/mimir/config.yaml:ro \
  -v mimir_data:/var/mimir \
  -p 8080:8080 \
  dhi.io/mimir:<tag> \
  --config.file=/etc/mimir/config.yaml \
  --target=all

If you mount a volume to a custom path, Docker auto-creates the target as root:root, which the nonroot user (UID 65532) cannot write to. Pre-chown the volume before starting Mimir:

$ docker volume create mimir_data
$ docker run --rm -v mimir_data:/data --user 0 \
    dhi.io/busybox:<tag> chown -R 65532:65532 /data
$ docker run -d --name mimir \
  -v /path/to/mimir.yaml:/etc/mimir/config.yaml:ro \
  -v mimir_data:/data \
  -p 8080:8080 \
  dhi.io/mimir:<tag> \
  --config.file=/etc/mimir/config.yaml \
  --target=all

For host bind-mounts, run chown -R 65532:65532 on the host directory before starting the container.

Run with Prometheus using Docker Compose

Run Prometheus and Mimir together using Docker Compose. Prometheus remote-writes metrics to Mimir, and Mimir exposes a Prometheus-compatible query API so Grafana can query both.

services:
  mimir:
    image: dhi.io/mimir:<tag>
    command:
      - --config.file=/etc/mimir/config.yaml
      - --target=all
    volumes:
      - ./mimir.yaml:/etc/mimir/config.yaml:ro
      - mimir_data:/var/mimir
    ports:
      - 8080:8080

  prometheus:
    image: prom/prometheus:latest
    volumes:
      - ./prometheus.yml:/etc/prometheus/prometheus.yml:ro
    ports:
      - 9090:9090

volumes:
  mimir_data: {}

In prometheus.yml, add a remote write section pointing to Mimir's push endpoint:

remote_write:
  - url: http://mimir:8080/api/v1/push
    headers:
      X-Scope-OrgID: anonymous

Mimir's query API is Prometheus-compatible; configure it as a Prometheus data source in Grafana at http://mimir:8080/prometheus.

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

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 mimir

Or mount debugging tools with the Image Mount feature:

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

For Mimir specifically, most operational inspection can also be done through the HTTP API without a shell: /ready, /metrics, /config, /runtime-config, /memberlist, and the full Prometheus-compatible query API.

Image variants

Docker 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:

  • Run as a 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 tag 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

• 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.

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. 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.

2. 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.

3. 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.

4. Install additional packages.

   Docker 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.

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.