dapr scheduler

This image includes:

• the dapr-scheduler binary at /usr/local/bin/dapr-scheduler
• an upstream-compatible /scheduler path for manifests or command overrides that expect the upstream binary location

Configuration reference

The scheduler flag set changes over time, so this guide does not duplicate a static flag table. Use the upstream Dapr documentation linked above for configuration guidance, and inspect the scheduler help output in your environment when you need the exact CLI surface for the image version you are running.

Run a standalone scheduler

When you run the scheduler directly as a nonroot container, provide a writable --etcd-data-dir. The upstream default is a relative ./data path, which is not appropriate for a minimal runtime image launched from /.

docker run --rm \
  -p 8080:8080 \
  -p 50006:50006 \
  registry.ghost-prod.alphabravo.io/ghost-base/dapr-scheduler:1 \
  --etcd-data-dir /tmp/dapr-scheduler

After startup, the health endpoint is available at:

$ curl http://localhost:8080/healthz

If you need scheduler state to survive container restarts, mount a writable directory or volume and point --etcd-data-dir at that location instead of /tmp.

Upstream compatibility note

The upstream daprio/scheduler image does not define an entrypoint, so direct docker run usage normally looks like /scheduler --help or /scheduler --etcd-data-dir ....

The hardened image sets the entrypoint to dapr-scheduler, so you can pass scheduler flags directly without adding an explicit binary path or overriding the entrypoint.

The upstream /scheduler path is still preserved for compatibility with manifests that explicitly override the command. For example, a manifest can continue to point at the upstream binary path:

containers:
  - name: scheduler
    image: registry.ghost-prod.alphabravo.io/ghost-base/dapr-scheduler:1
    command: ["/scheduler"]
    args:
      - --etcd-data-dir
      - /tmp/dapr-scheduler

Image variants

Ghost 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

• 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.

Migrate to a Ghost hardened image

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:

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. 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.

3. For multi-stage Dockerfiles, update the runtime image in your Dockerfile.

   If you're using a multi-stage build, update the runtime stage to use a non-dev hardened image. This ensures your production containers run with minimal attack surface.

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 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.

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

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.