spiffe csi driver

First follow the authentication instructions for DHI in Kubernetes.

Deploy with the SPIFFE Helm Charts

The spiffe-csi-driver image is bundled within the SPIRE chart in the helm-charts-hardened repository. Override the CSI driver image to use Ghost hardened images via a values.yaml file.

Create a values.yaml file and configure the SPIFFE CSI Driver to use your Ghost hardened image. Replace <tag> with the image variant you want to use.

spiffe-csi-driver:
  image:
    registry: registry.ghost-prod.alphabravo.io
    repository: spiffe-csi-driver
    tag: <tag>

Install the SPIRE CRDs and stack with your custom values:

$ helm upgrade --install -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/ -f values.yaml

Verify the SPIFFE CSI Driver DaemonSet is running:

$ kubectl get daemonset -n spire -l app.kubernetes.io/name=spiffe-csi-driver

Verify the deployment is using the DHI image:

$ kubectl -n spire get pods -l app.kubernetes.io/name=spiffe-csi-driver \
    -o jsonpath='{.items[*].spec.containers[0].image}'

Deploy with a standalone DaemonSet manifest

If you are not using Helm, you can deploy the SPIFFE CSI Driver manually. The following manifest registers the CSIDriver resource and deploys the driver alongside the CSI Node Driver Registrar sidecar. Update the image references to point to your Ghost hardened images. Replace <tag> with a spiffe-csi-driver variant tag and <registrar-tag> with a compatible csi-node-driver-registrar tag (for example 0.2 and 2); the sidecar uses a different version line than the driver.

apiVersion: v1
kind: ServiceAccount
metadata:
  name: spiffe-csi-driver
  namespace: spire
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: spiffe-csi-driver
  namespace: spire
  labels:
    app: spiffe-csi-driver
spec:
  selector:
    matchLabels:
      app: spiffe-csi-driver
  template:
    metadata:
      labels:
        app: spiffe-csi-driver
    spec:
      serviceAccountName: spiffe-csi-driver
      containers:
        - name: spiffe-csi-driver
          image: registry.ghost-prod.alphabravo.io/ghost-base/spiffe-csi-driver:<tag>
          imagePullPolicy: IfNotPresent
          args:
            - "-workload-api-socket-dir"
            - "/spire-agent-socket"
            - "-csi-socket-path"
            - "/spiffe-csi/csi.sock"
          env:
            - name: MY_NODE_NAME
              valueFrom:
                fieldRef:
                  fieldPath: spec.nodeName
          volumeMounts:
            - mountPath: /spire-agent-socket
              name: spire-agent-socket-dir
              readOnly: true
            - mountPath: /spiffe-csi
              name: spiffe-csi-socket-dir
            - mountPath: /var/lib/kubelet/pods
              mountPropagation: Bidirectional
              name: mountpoint-dir
          securityContext:
            readOnlyRootFilesystem: true
            capabilities:
              drop:
                - ALL
            privileged: true
        - name: node-driver-registrar
          image: registry.ghost-prod.alphabravo.io/ghost-base/csi-node-driver-registrar:<registrar-tag>
          imagePullPolicy: IfNotPresent
          args:
            - "-csi-address"
            - "/spiffe-csi/csi.sock"
            - "-kubelet-registration-path"
            - "/var/lib/kubelet/plugins/csi.spiffe.io/csi.sock"
          volumeMounts:
            - mountPath: /spiffe-csi
              name: spiffe-csi-socket-dir
            - name: kubelet-plugin-registration-dir
              mountPath: /registration
      volumes:
        - name: spire-agent-socket-dir
          hostPath:
            path: /run/spire/agent-sockets
            type: DirectoryOrCreate
        - name: spiffe-csi-socket-dir
          hostPath:
            path: /var/lib/kubelet/plugins/csi.spiffe.io
            type: DirectoryOrCreate
        - name: mountpoint-dir
          hostPath:
            path: /var/lib/kubelet/pods
            type: Directory
        - name: kubelet-plugin-registration-dir
          hostPath:
            path: /var/lib/kubelet/plugins_registry
            type: Directory
---
apiVersion: storage.k8s.io/v1
kind: CSIDriver
metadata:
  name: "csi.spiffe.io"
spec:
  attachRequired: false
  podInfoOnMount: true
  fsGroupPolicy: None
  volumeLifecycleModes:
    - Ephemeral

Apply the manifest:

$ kubectl apply -f spiffe-csi-driver.yaml

Use the SPIFFE CSI Driver in a workload pod

Once the driver is registered, workload pods can request the SPIFFE Workload API socket by declaring an ephemeral inline volume:

apiVersion: v1
kind: Pod
metadata:
  name: my-workload
spec:
  containers:
    - name: my-app
      image: my-app:latest
      volumeMounts:
        - name: spiffe-workload-api
          mountPath: /run/spiffe/sockets
          readOnly: true
  volumes:
    - name: spiffe-workload-api
      csi:
        driver: csi.spiffe.io
        readOnly: true

Verify the CSI Driver registration

Confirm the CSI driver is registered with the Kubernetes API server:

$ kubectl get csidriver csi.spiffe.io

Check the SPIFFE CSI Driver logs for mount activity:

$ kubectl logs -n spire -l app=spiffe-csi-driver -c spiffe-csi-driver

Note: The SPIFFE CSI Driver must run as privileged: true in its security context because it performs bind mounts into other pods' namespaces. The registry.ghost-prod.alphabravo.io/ghost-base/spiffe-csi-driver image runs as nonroot (UID 65532) by default, but Kubernetes will apply the privileged security context defined in the pod spec. Ensure your cluster policy allows privileged DaemonSet containers in the namespace where the driver is deployed.

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.