spiffe-csi-driver

packaged by Chainguard

Chainguard Container for spiffe-csi-driver

A minimal, secure container image for the SPIFFE CSI Driver, a Kubernetes node plugin that exposes the SPIFFE Workload API socket to pods through ephemeral inline CSI volumes.

Chainguard Containers are regularly-updated, secure-by-default container images.

Download this Container Image

For those with access, this container image is available on cgr.dev:

docker pull cgr.dev/ORGANIZATION/spiffe-csi-driver:latest

Be sure to replace the ORGANIZATION placeholder with the name used for your organization's private repository within the Chainguard Registry.

Compatibility Notes

Chainguard's spiffe-csi-driver image is a drop-in replacement for the upstream ghcr.io/spiffe/spiffe-csi-driver image, with two differences:

• The driver binary is available at /spiffe-csi-driver, the path the upstream image uses as its entrypoint, and also at /usr/bin/spiffe-csi-driver.
• The image is built on Wolfi rather than scratch, so it ships a minimal base layer and a complete package SBOM.

Like the upstream image, this image runs as root. Publishing a volume bind-mounts the SPIRE agent's Workload API socket directory into the workload container, which requires CAP_SYS_ADMIN, so the driver's pod spec must set securityContext.privileged: true.

Prerequisites

• A Kubernetes cluster running a SPIRE server and agent. The driver mounts the socket directory the agent owns; it does not issue identities itself.
• The csi-node-driver-registrar sidecar, which registers the driver with the kubelet under the plugin name csi.spiffe.io.

Getting Started

The driver is a Kubernetes node plugin, so it does little on its own, but you can confirm the image starts and serves the CSI gRPC API on a Unix domain socket:

docker run --rm -d --name spiffe-csi-driver \
  cgr.dev/ORGANIZATION/spiffe-csi-driver:latest \
  -node-id demo-node \
  -workload-api-socket-dir /tmp \
  -csi-socket-path /tmp/csi.sock

docker logs spiffe-csi-driver

The driver logs Starting. and then Listening..., which it emits only after binding the CSI socket.

Deploying with the SPIRE Helm chart

The driver ships as the spiffe-csi-driver subchart of the SPIRE hardened Helm chart. The subchart's image is overridden under its own key.

Create a values.yaml pointing the subchart at this image:

spiffe-csi-driver:
  image:
    registry: cgr.dev
    repository: ORGANIZATION/spiffe-csi-driver
    tag: latest

Then install the CRDs and the chart:

helm upgrade --install --create-namespace -n spire spire-crds spire-crds \
  --repo https://spiffe.github.io/helm-charts-hardened/

helm upgrade --install -n spire spire spire \
  --repo https://spiffe.github.io/helm-charts-hardened/ \
  --values values.yaml

Once the DaemonSet is ready, the kubelet has a registered CSI driver:

kubectl get csidriver csi.spiffe.io

Mounting the Workload API into a pod

Workloads consume the driver through an ephemeral inline volume. The volume must be read-only; the driver rejects any other request.

kubectl apply -n spire -f - <<'EOF'
apiVersion: v1
kind: Pod
metadata:
  name: csi-mount-check
spec:
  containers:
    - name: workload
      image: cgr.dev/ORGANIZATION/busybox:latest
      command: ["sleep", "600"]
      volumeMounts:
        - name: spiffe-workload-api
          mountPath: /spiffe-workload-api
          readOnly: true
  volumes:
    - name: spiffe-workload-api
      csi:
        driver: csi.spiffe.io
        readOnly: true
EOF

kubectl exec -n spire csi-mount-check -- ls /spiffe-workload-api

The mount contains the SPIRE agent socket, which SPIFFE-aware libraries reach through SPIFFE_ENDPOINT_SOCKET=unix:///spiffe-workload-api/spire-agent.sock.

Configuration

The driver is configured entirely through command-line flags; it reads no configuration file. The two that matter most are the socket paths, which must agree with the volumes the DaemonSet mounts:

• -workload-api-socket-dir is the directory holding the SPIRE agent socket, mounted from the host. This is the directory the driver bind-mounts into each workload.
• -csi-socket-path is where the driver serves the CSI gRPC API, mounted from the kubelet plugin directory so csi-node-driver-registrar can find it.

-node-id identifies the node to the kubelet. Rather than templating it per node, leave it unset and let the driver read it from the environment variable named by -node-id-env (MY_NODE_NAME by default), populated from the downward API:

env:
  - name: MY_NODE_NAME
    valueFrom:
      fieldRef:
        fieldPath: spec.nodeName

Use -plugin-name only if you need to register under a name other than csi.spiffe.io; it must match the driver field of every workload's CSI volume.

Documentation and Resources

• spiffe-csi upstream repository
• SPIRE agent deployment documentation
• SPIRE hardened Helm charts

What are Chainguard Containers?

Chainguard's free tier of Starter container images are built with Wolfi, our minimal Linux undistro.

All other Chainguard Containers are built with Chainguard OS, Chainguard's minimal Linux operating system designed to produce container images that meet the requirements of a more secure software supply chain.

The main features of Chainguard Containers include:

• Minimal design, without unnecessary software bloat
• Daily builds to ensure container images are up-to-date with available security patches
• High quality build-time SBOMs attesting to the provenance of all artifacts within the image
• Verifiable signatures provided by Sigstore
• Reproducible builds with Cosign and apko (read more about reproducibility)

For cases where you need container images with shells and package managers to build or debug, most Chainguard Containers come paired with a development, or -dev, variant.

In all other cases, including Chainguard Containers tagged as :latest or with a specific version number, the container images include only an open-source application and its runtime dependencies. These minimal container images typically do not contain a shell or package manager.

Although the -dev container image variants have similar security features as their more minimal versions, they include additional software that is typically not necessary in production environments. We recommend using multi-stage builds to copy artifacts from the -dev variant into a more minimal production image.

Need additional packages?

To improve security, Chainguard Containers include only essential dependencies. Need more packages? Chainguard customers can use Custom Assembly to add packages, either through the Console, chainctl, or API.

To use Custom Assembly in the Chainguard Console: navigate to the image you'd like to customize in your Organization's list of images, and click on the Customize image button at the top of the page.

Learn More

Refer to our Chainguard Containers documentation on Chainguard Academy. Chainguard also offers VMs and Libraries — contact us for access.

Trademarks

This software listing is packaged by Chainguard. The trademarks set forth in this offering are owned by their respective companies, and use of them does not imply any affiliation, sponsorship, or endorsement by such companies.