Chainguard Container for local-volume-provisioner

Static provisioner of local 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/local-volume-provisioner: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 local-volume-provisioner Chainguard Image is comparable to the upstream local-volume-provisioner image maintained by the Kubernetes SIG Storage community, with the following key differences:

Non-root Execution

Difference: This Chainguard Image runs as a non-root user (UID 65532) instead of root (UID 0).

Why this change exists: Running containers as non-root is a security best practice that reduces the attack surface by limiting the privileges available to a compromised container. This aligns with the principle of least privilege and helps meet compliance requirements for secure container deployments.

Benefits:

• Reduced security risk if the container is compromised
• Better alignment with Pod Security Standards and security policies
• Compliance with organizational security requirements that prohibit root containers

Breaking change: If you are migrating from an upstream image that runs as root, you may need to adjust your deployment. The non-root user requires explicit permissions to access host paths and perform volume management operations.

Required adjustments:

• Host paths mounted into the container must have appropriate permissions (readable/writable by UID 65532)
• Some file system operations may require init containers with elevated privileges to prepare directories
• Security contexts and volume mount options may need configuration to grant necessary permissions

If you encounter permission errors, review your volume mounts, security contexts, and host path permissions to ensure compatibility with non-root execution.

Prerequisites

Before using this image, you will need:

• A Kubernetes cluster (version 1.23 or later recommended)
• kubectl configured to access your cluster
• Host paths on nodes designated for local volume storage
• Appropriate permissions to create StorageClasses and DaemonSets

For local testing, this guide uses k3d to create a lightweight Kubernetes cluster.

For detailed information about the local volume provisioner, refer to the upstream documentation.

Getting Started

To be able to test the local volume provisioner, you need to have a Kubernetes cluster running. You can use k3d to create a local cluster.

Create a local cluster

k3d create cluster

Deploy the local volume provisioner

# Create the necessary StorageClass
kubectl apply -f https://raw.githubusercontent.com/kubernetes-sigs/sig-storage-local-static-provisioner/master/deployment/kubernetes/example/default_example_storageclass.yaml

# Create the local volume provisioner
kubectl apply -f https://raw.githubusercontent.com/kubernetes-sigs/sig-storage-local-static-provisioner/master/deployment/kubernetes/example/default_example_provisioner_generated.yaml

# Change the provisioner image to the Chainguard image
kubectl set image daemonset/local-volume-provisioner provisioner="cgr.dev/ORGANIZATION/local-volume-provisioner:latest"

Please ensure that the local volume provisioner is running before moving to the next step:

kubectl rollout status daemonset/local-volume-provisioner --timeout=120s

So, if everything is running, you should shell/exec into the nodes and do the following:

# Get server and worker node names from k3d, filtering by role
node_names=$(k3d node list -o json | jq -r '.[] | select(.role == "server" or .role == "agent") | .name')

# Loop over each node name and execute the commands
for node in $node_names; do
    echo "Configuring node: $node"

    # Create directory
    docker exec $node mkdir -p /mnt/fast-disks/vol1

    # Mount tmpfs
    docker exec $node mount -t tmpfs vol1 /mnt/fast-disks/vol1

    echo "Configuration complete for node: $node"
done

Once you have the local disks mounted, you should see the PVs created:

kubectl get pv

That's it! You have the local-volume-provisioner running and managing the local disks on your cluster.

Configuration

The local-volume-provisioner is configured through a ConfigMap that defines discovery directories and storage classes. Here's an example of configuring the provisioner to use a specific directory pattern with proper permissions for non-root execution:

apiVersion: v1
kind: ConfigMap
metadata:
  name: local-provisioner-config
  namespace: default
data:
  storageClassMap: |
    fast-disks:
      hostDir: /mnt/fast-disks
      mountDir: /mnt/fast-disks
      blockCleanerCommand:
        - "/scripts/shred.sh"
        - "2"
      volumeMode: Filesystem
      fsType: ext4

Key configuration considerations for non-root execution:

When using this Chainguard Image, ensure that the hostDir paths have appropriate permissions. You may need to use an init container to prepare directories with the correct ownership:

apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: local-volume-provisioner
spec:
  template:
    spec:
      initContainers:
      - name: prepare-dirs
        image: cgr.dev/ORGANIZATION/busybox:latest
        command:
        - sh
        - -c
        - |
          chown -R 65532:65532 /mnt/fast-disks
          chmod -R 755 /mnt/fast-disks
        volumeMounts:
        - name: local-disks
          mountPath: /mnt/fast-disks
        securityContext:
          runAsUser: 0
          privileged: true
      containers:
      - name: provisioner
        image: cgr.dev/ORGANIZATION/local-volume-provisioner:latest
        securityContext:
          runAsUser: 65532
          runAsNonRoot: true
        # ... rest of configuration

This approach uses a privileged init container to set up directory permissions once, allowing the main provisioner container to run securely as non-root. This pattern provides the security benefits of non-root execution while handling the necessary privileged operations during initialization.

For complete configuration options, refer to the upstream configuration documentation.

Documentation and Resources

• Kubernetes Local Persistent Volumes - Official Kubernetes documentation on local volumes
• Local Volume Provisioner GitHub Repository - Upstream project documentation
• Chainguard Academy - Learn more about Chainguard Images and secure container practices
• Working with Chainguard Images - General guidance on using Chainguard Images

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.

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