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/aws-controllers-k8s-sqs-controller:<tag>
• Mirrored image: <your-namespace>/dhi-aws-controllers-k8s-sqs-controller:<tag>

For the examples, you must first use docker login dhi.io to authenticate to the registry to pull the images.

AWS Controllers for Kubernetes (ACK) SQS controller runs in a cluster and reconciles Queue custom resources into Amazon SQS queues. This image replaces public.ecr.aws/aws-controllers-k8s/sqs-controller on the 1.x line. It is a drop-in for the upstream release image: the same entrypoint, working directory and flags. The upstream project documents the custom resources, IAM permissions and Helm chart at https://github.com/aws-controllers-k8s/sqs-controller⁠.

The runtime tags are dhi.io/aws-controllers-k8s-sqs-controller:1-alpine3.24 (Alpine 3.24) and dhi.io/aws-controllers-k8s-sqs-controller:1-debian13 (Debian 13). The version tags, such as 1.9.0-debian13, pin the release.

Start an ACK SQS controller image

The entrypoint is /bin/controller, and the image sets no command. Runtime tags run as user 65532 and contain no shell.

Basic usage

docker run --rm dhi.io/aws-controllers-k8s-sqs-controller:1-debian13 --help

The controller needs an AWS Region and AWS credentials before it starts. Without a Region it exits with AWS region is missing. Pass --aws-region, or set AWS_REGION, and provide credentials through the usual AWS SDK variables such as AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY, or through IAM roles for service accounts in a cluster.

Outside a cluster, point the KUBECONFIG environment variable at a kubeconfig file. The controller reads the in-cluster configuration when no kubeconfig is set.

Credentials from a file are read from /.aws/credentials, the same path upstream uses, or from the path in AWS_SHARED_CREDENTIALS_FILE. Mount the file read-only and make it readable by UID 65532. For example, mode 0644 is readable by UID 65532.

Install with the upstream Helm chart

Install the upstream chart and point its image at this image. The chart runs the controller as a non-root user with a read-only root filesystem, so use a runtime tag. Dev tags run as root and the pod is rejected.

helm install ack-sqs-controller oci://public.ecr.aws/aws-controllers-k8s/sqs-chart \
  --version 1.9.0 \
  --namespace ack-system --create-namespace \
  --set image.repository=dhi.io/aws-controllers-k8s-sqs-controller \
  --set image.tag=1.9.0-debian13 \
  --set aws.region=us-east-1

The chart does not set runAsUser, so the numeric nonroot user of the image is what the pod runs as. Create the dhi-pull-secret image pull secret for dhi.io in the target namespace first, and add it to the chart with --set image.pullSecrets[0]=dhi-pull-secret when the registry requires it. The chart reads the secret names from image.pullSecrets, as plain strings.

Manage a queue

After the controller is ready, a Queue custom resource creates a queue in AWS. The controller reports ACK.ResourceSynced on the resource once the queue exists.

apiVersion: sqs.services.k8s.aws/v1alpha1
kind: Queue
metadata:
  name: orders
  namespace: default
spec:
  queueName: orders
  delaySeconds: "5"

Deleting the resource deletes the queue.

Health and metrics

The controller serves Prometheus metrics on port 8080 (--metrics-addr) and health probes on port 8081 (--healthz-addr). The image declares both ports. The chart probes /healthz and /readyz on 8081.

To read the metrics from your workstation, forward the port to the controller Deployment. With the release name ack-sqs-controller, the chart names the Deployment ack-sqs-controller-sqs-chart:

kubectl -n ack-system port-forward deploy/ack-sqs-controller-sqs-chart 8080

Then read the metrics from another terminal:

curl -s http://localhost:8080/metrics | grep ack_outbound_api_requests_total

Non-hardened images vs. Docker Hardened Images

• The images are built for linux/amd64 and linux/arm64. The upstream image runs as UID 1000. This image runs as nonroot UID 65532, which is the Docker Hardened Images convention. The chart's runAsNonRoot check accepts any numeric non-zero UID, and the controller writes no files, so the UID change needs no volume or ownership changes for its own output. Credential and kubeconfig files you mount from an upstream setup must be readable by UID 65532, not only by UID 1000. The image keeps HOME at / as upstream does, so the default credentials file is /.aws/credentials and the default AWS config file is /.aws/config. Set AWS_SHARED_CREDENTIALS_FILE to read the credentials from another path.
• The upstream binary is named controller, and the packaged binary is named ack-sqs-controller. The image keeps the upstream entrypoint /bin/controller, so manifests that run the entrypoint or ./bin/controller keep working. On the Alpine tags, /usr/bin/controller is a symlink to /usr/bin/ack-sqs-controller, the same as on the Debian tags, so both upstream invocation paths work on both distros. Use /bin/controller, /usr/bin/controller, or /usr/bin/ack-sqs-controller there.
• The Debian tags install Debian's tzdata without tzdata-legacy, so legacy zone names such as US/Eastern are missing and TZ set to one falls back to UTC. Use a canonical name such as America/New_York, or an Alpine tag.

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. 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.

   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.