local path provisioner

Run the local-path-provisioner container

Local Path Provisioner is designed to run inside a Kubernetes cluster. It requires access to the Kubernetes API and a properly configured service account.

To display version information:

docker run --rm registry.ghost-prod.alphabravo.io/ghost-base/local-path-provisioner:<tag> --version

To display help information:

docker run --rm registry.ghost-prod.alphabravo.io/ghost-base/local-path-provisioner:<tag> --help

Deploy Local Path Provisioner in Kubernetes

The recommended deployment method is to apply the upstream manifest and replace the image reference with the Docker Hardened image.

1. Download the manifest for your target release:

curl -LO https://raw.githubusercontent.com/rancher/local-path-provisioner/v<VERSION>/deploy/local-path-storage.yaml

1. Replace the upstream image reference with the Docker Hardened image:

sed -i 's|rancher/local-path-provisioner:v<VERSION>|registry.ghost-prod.alphabravo.io/ghost-base/local-path-provisioner:<tag>|g' local-path-storage.yaml

1. Apply the manifest:

kubectl apply -f local-path-storage.yaml

1. Verify the provisioner is running:

kubectl -n local-path-storage get pod

You should see output similar to:

NAME                                     READY   STATUS    RESTARTS   AGE
local-path-provisioner-d744ccf98-xfcbk   1/1     Running   0          30s

Note: The dev variants of this image run as root. If the deployment manifest includes runAsNonRoot: true in the pod security context, dev variants will not start. Modify the security context to set runAsNonRoot: false if you need to deploy a dev variant.

Configure storage paths

Local Path Provisioner reads its configuration from a ConfigMap named local-path-config in the local-path-storage namespace. The default configuration stores volumes under /opt/local-path-provisioner on every node. You can customize this per node using the nodePathMap field.

Example ConfigMap with per-node path customization:

apiVersion: v1
kind: ConfigMap
metadata:
  name: local-path-config
  namespace: local-path-storage
data:
  config.json: |-
    {
      "nodePathMap": [
        {
          "node": "DEFAULT_PATH_FOR_NON_LISTED_NODES",
          "paths": ["/opt/local-path-provisioner"]
        },
        {
          "node": "node1",
          "paths": ["/data/local-path"]
        },
        {
          "node": "node2",
          "paths": []
        }
      ]
    }
  setup: |-
    #!/bin/sh
    set -eu
    mkdir -m 0777 -p "$VOL_DIR"
  teardown: |-
    #!/bin/sh
    set -eu
    rm -rf "$VOL_DIR"
  helperPod.yaml: |-
    apiVersion: v1
    kind: Pod
    metadata:
      name: helper-pod
    spec:
      priorityClassName: system-node-critical
      tolerations:
        - key: node.kubernetes.io/disk-pressure
          operator: Exists
          effect: NoSchedule
      containers:
      - name: helper-pod
        image: busybox
        imagePullPolicy: IfNotPresent

Notes on the ConfigMap:

• Nodes listed with an empty paths array ([]) will be excluded from provisioning.
• If a node is not listed, the DEFAULT_PATH_FOR_NON_LISTED_NODES paths are used.
• When multiple paths are specified for a node, the provisioner chooses one randomly.
• Configuration changes are reloaded automatically without restarting the provisioner.

Use a custom StorageClass

By default, the provisioner registers the local-path StorageClass. You can define additional StorageClasses that pin provisioning to a specific node path or use a custom volume naming pattern:

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: ssd-local-path
provisioner: rancher.io/local-path
parameters:
  nodePath: /data/ssd
  pathPattern: "{{ .PVC.Namespace }}/{{ .PVC.Name }}/"
volumeBindingMode: WaitForFirstConsumer
reclaimPolicy: Delete

To select hostPath or local volume type, add an annotation to the PVC:

annotations:
  volumeType: local

If neither annotation is present, the provisioner defaults to hostPath.

Provision a PersistentVolume

After the provisioner is deployed, create a PVC using the local-path StorageClass:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: local-path-pvc
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: local-path
  resources:
    requests:
      storage: 2Gi

Apply the PVC and verify it is bound:

kubectl apply -f pvc.yaml
kubectl get pvc local-path-pvc

A PersistentVolume is created automatically on the node where the workload is scheduled (with volumeBindingMode: WaitForFirstConsumer) or immediately (with volumeBindingMode: Immediate).

Monitor the provisioner

Follow the provisioner logs to observe volume provisioning and teardown events:

kubectl -n local-path-storage logs -f -l app=local-path-provisioner

Image variants

Ghost hardened images come in different variants depending on their intended use.

• 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 the 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 variant 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.

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.