kubernetes-csi-driver-smb-fips

packaged by Chainguard

Chainguard Container for kubernetes-csi-driver-smb-fips

Minimal image for the Kubernetes SMB CSI driver, built with Chainguard's FIPS Go toolchain and OpenSSL configuration.

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/kubernetes-csi-driver-smb-fips:latest

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

Compatibility Notes

The cgr.dev/ORGANIZATION/kubernetes-csi-driver-smb-fips image replaces the Linux smbplugin image published at gcr.io/k8s-staging-sig-storage/smbplugin and registry.k8s.io/sig-storage/smbplugin. It preserves the /smbplugin entrypoint, root user, and / working directory. CIFS mount helpers and the utilities used by the driver are included.

The default image omits upstream's shell, e2fsprogs, xfsprogs, udev, and full util-linux suite. It includes mount and umount from util-linux, mount.cifs, and coreutils for operations such as volume cloning. The driver mounts existing SMB shares and invokes these utilities directly; it does not need a shell, local filesystem formatting tools, or device management services. Omitting those tools reduces image size and attack surface. Use a -dev tag when you need a shell for troubleshooting.

The image provides /etc/krb5.conf with the upstream credential-cache location, FILE:/var/lib/kubelet/kerberos/krb5cc_%{uid}. CIFS upcalls run through the host's request-key and cifs.upcall; namespace-aware upcalls read this configuration after entering the driver container. Follow upstream's node-side Kerberos setup, including the shared credential directory and host cache-location configuration. For custom Kerberos configuration, use a Helm post-renderer to add a ConfigMap volume to the csi-smb-node DaemonSet. Mount the ConfigMap's krb5.conf key read-only at /etc/krb5.conf in the smb container using subPath: krb5.conf. Use the same post-renderer for subsequent Helm upgrades.

FIPS Support

This variant uses Chainguard's FIPS Go toolchain and OpenSSL configuration. See Chainguard's FIPS guidance for details about FIPS support in Chainguard Containers.

SMB authentication, signing, and encryption also depend on the host kernel's CIFS client and host Kerberos helpers. The image's userspace FIPS configuration does not configure the host. Use an appropriately configured host and SMB server when FIPS requirements apply to storage traffic, and configure the chart's CSI sidecars separately when your deployment requires FIPS variants throughout.

Prerequisites

Use a Kubernetes cluster with Linux nodes, Helm 3, and access to an existing SMB share. The nodes must support CIFS mounts and allow the driver's privileged pods and bidirectional mount propagation. Configure registry credentials for your organization before installing. This image supports Linux nodes; disable the chart's Windows DaemonSet when using the image override below.

Getting Started

Create a values file that selects the FIPS driver image while preserving the chart's CSI sidecars:

cat > smb-values.yaml <<'EOF'
image:
  smb:
    repository: cgr.dev/ORGANIZATION/kubernetes-csi-driver-smb-fips
    tag: "latest"
windows:
  enabled: false
EOF

helm repo add csi-driver-smb https://raw.githubusercontent.com/kubernetes-csi/csi-driver-smb/master/charts
helm repo update csi-driver-smb
helm upgrade --install csi-driver-smb csi-driver-smb/csi-driver-smb \
  --namespace kube-system --values smb-values.yaml
kubectl rollout status deployment/csi-smb-controller --namespace kube-system
kubectl rollout status daemonset/csi-smb-node --namespace kube-system

Configuration

This example mounts an existing SMB share using username/password authentication. Replace //smb.example.com/share with a share reachable from your Linux nodes, and replace the credentials with an account that can create directories and read and write files on that share. Create the credentials Secret in the workload's namespace:

cat > smb-secret.yaml <<'EOF'
apiVersion: v1
kind: Secret
metadata:
  name: smbcreds
  namespace: default
type: Opaque
stringData:
  username: "REPLACE_WITH_SMB_USERNAME"
  password: "REPLACE_WITH_SMB_PASSWORD"
EOF
kubectl apply -f smb-secret.yaml

Create a second Helm values file with a storageClasses entry. The provisioner uses the Secret to create a directory for each volume; the node plugin uses it to mount that directory. The UID, GID, and mode options give the example pod access to the mounted files. Retain preserves the volume's data when the PVC is deleted:

cat > smb-storage-values.yaml <<'EOF'
storageClasses:
  - name: smb
    parameters:
      source: "//smb.example.com/share"
      csi.storage.k8s.io/provisioner-secret-name: smbcreds
      csi.storage.k8s.io/provisioner-secret-namespace: default
      csi.storage.k8s.io/node-stage-secret-name: smbcreds
      csi.storage.k8s.io/node-stage-secret-namespace: default
    reclaimPolicy: Retain
    volumeBindingMode: Immediate
    mountOptions:
      - vers=3.0
      - uid=1000
      - gid=1000
      - dir_mode=0770
      - file_mode=0660
      - noserverino
EOF

helm upgrade --install csi-driver-smb csi-driver-smb/csi-driver-smb \
  --namespace kube-system --values smb-values.yaml --values smb-storage-values.yaml

Keep smb-values.yaml from Getting Started in this command so the driver image override stays in effect. Create a PVC and a pod that mounts it at /data, writes a file, and prints its contents:

cat > smb-workload.yaml <<'EOF'
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: smb-data
  namespace: default
spec:
  storageClassName: smb
  accessModes: [ReadWriteMany]
  resources:
    requests:
      storage: 1Gi
---
apiVersion: v1
kind: Pod
metadata:
  name: smb-example
  namespace: default
spec:
  restartPolicy: Never
  nodeSelector:
    kubernetes.io/os: linux
  securityContext:
    runAsNonRoot: true
    runAsUser: 1000
    runAsGroup: 1000
  containers:
    - name: writer
      image: cgr.dev/chainguard/busybox:latest
      command: ["sh", "-ec"]
      args:
        - |
          printf '%s\n' 'Hello from SMB' > /data/hello.txt
          cat /data/hello.txt
      volumeMounts:
        - name: smb
          mountPath: /data
  volumes:
    - name: smb
      persistentVolumeClaim:
        claimName: smb-data
EOF

kubectl apply -f smb-workload.yaml
kubectl wait --namespace default --for=jsonpath='{.status.phase}'=Bound \
  pvc/smb-data --timeout=180s
kubectl wait --namespace default --for=jsonpath='{.status.phase}'=Succeeded \
  pod/smb-example --timeout=180s
kubectl logs --namespace default smb-example

The example uses the public BusyBox image as a client. Successful output is:

Hello from SMB

For a cluster with a nonstandard kubelet directory, set linux.kubelet in the values file so the driver registers its socket and mounts volumes in the directory the kubelet uses. Consult the upstream driver parameters for mount options and Kerberos configuration.

Documentation and Resources

• SMB CSI driver source
• Helm chart configuration
• Chainguard FIPS guidance

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