object storage sidecar

Installation requirements vary by driver and deployment platform. Before proceeding, ensure your chosen driver is compatible with your Kubernetes version and COSI API version. Consult each driver's documentation for specific requirements, as many provide Helm charts or Kubernetes manifests for easier deployment. See the Driver Installation Guide for general guidance.

When properly deployed, the sidecar connects to the driver and begins managing COSI resources in the cluster. For full functionality, you'll also need to install the COSI controller manager and configure appropriate RBAC permissions.

Prerequisites

1. A running Kubernetes cluster
2. kubectl configured to access your cluster
3. A namespace created (e.g., kubectl create namespace <cosi-namespace>)

Step 1: Load the images

For minikube or similar local clusters, load the images:

minikube image load registry.ghost-prod.alphabravo.io/ghost-base/objectstorage-sidecar:<tag>
minikube image load registry.ghost-prod.alphabravo.io/ghost-base/seaweedfs-cosi-driver:<tag>

For other Kubernetes distributions, ensure the images are available in your container registry or can be pulled by your cluster nodes.

Step 2: Deploy the COSI provisioner

Deploy both the COSI sidecar and driver together:

kubectl apply -f - <<'EOF'
apiVersion: apps/v1
kind: Deployment
metadata:
  name: cosi-provisioner
  namespace: <cosi-namespace>
spec:
  replicas: 1
  selector:
    matchLabels:
      app: cosi-provisioner
  template:
    metadata:
      labels:
        app: cosi-provisioner
    spec:
      containers:
      - name: seaweedfs-cosi-driver
        image: registry.ghost-prod.alphabravo.io/ghost-base/seaweedfs-cosi-driver:<tag>
        args:
          - "-v=5"
          - "-logtostderr"
        env:
          - name: COSI_ENDPOINT
            value: "unix:///var/lib/cosi/cosi.sock"
        volumeMounts:
          - name: socket-dir
            mountPath: /var/lib/cosi
      - name: cosi-sidecar
        image: registry.ghost-prod.alphabravo.io/ghost-base/objectstorage-sidecar:<tag>
        args:
          - "-d"
          - "unix:///var/lib/cosi/cosi.sock"
          - "-v"
          - "5"
        volumeMounts:
          - name: socket-dir
            mountPath: /var/lib/cosi
        resources:
          requests:
            cpu: 100m
            memory: 128Mi
          limits:
            cpu: 200m
            memory: 256Mi
      volumes:
        - name: socket-dir
          emptyDir: {}
EOF

Step 3: Verify the connection

Check that both containers are running:

kubectl get pods -n <cosi-namespace> -l app=cosi-provisioner

View the sidecar logs to confirm successful connection:

kubectl logs -n <cosi-namespace> -l app=cosi-provisioner -c cosi-sidecar

You should see a successful connection message:

"Successfully connected to driver" name="seaweedfs.objectstorage.k8s.io"

If you see leader election errors, this is expected when RBAC permissions or COSI CRDs are not yet configured. The connection between the sidecar and driver is working correctly.

Image variants

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:

  • 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 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.

   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

   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.

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.