K8s Local Storage Metrics Exporter

A Prometheus metrics exporter for Kubernetes storage providers that use host path storage, including openebs-hostpath, microk8s-hostpath, and standard storage classes for minikube, kind, and k3s. This exporter fills the gap left by standard Kubernetes monitoring solutions that don't provide visibility into local storage usage on worker nodes.

Features

• Exports local storage metrics in Prometheus format
• Supports multiple storage class providers
• Configurable update intervals
• Kubernetes-native deployment via Helm
• ServiceMonitor/PodMonitor for Prometheus Operator integration
• Grafana dashboard included

Quick Start

Prerequisites

• Kubernetes cluster
• Docker/container registry access
• Helm 3.x

Build and Push Container Image

REGISTRY=my-registry
# first docker login if needed
docker build -t ${REGISTRY}/local-storage-exporter:latest --platform=linux/amd64 . # change the platform and tag according to your needs
docker push ${REGISTRY}/local-storage-exporter:latest

Github Actions will automatically build and push the image and the helm chart to the GitHub Container Registry (GHCR) when changes are pushed to the main branch.

Deploy with Helm

Create a values.yaml file:

# (Required) Storage classes to monitor
storageClassNames: 
  - openebs-hostpath

# (Required) Host paths where PVs are stored
storagePaths: 
  - /var/openebs/local/

# Container image configuration
image:
  repository: ghcr.io/prokube/local-storage-exporter # Or your custom registry/repo
  # tag: "0.1.0"  # If omitted, defaults to the chart's appVersion
  pullPolicy: IfNotPresent

# Private registry authentication (optional)
imagePullSecrets:
  - name: your-registry-secret

# Metrics configuration
metricsPort: 9100
updateInterval: 15s  # Supported suffixes: ms, s, m, h
logLevel: info

# PVC label promotion (optional)
# List of PVC label keys to expose as individual Prometheus metric labels.
# Characters invalid in Prometheus label names (e.g. dots, slashes) are replaced with underscores.
# Example: a PVC label "app.kubernetes.io/name" becomes the metric label "app_kubernetes_io_name".
pvcLabels:
  promote: []
  # promote:
  #   - custom_label1
  #   - custom_label2
  # Also expose all remaining PVC labels (those not in the promote list) as a JSON blob
  # in a single "pvc_labels" metric label. Defaults to false.
  includeRemainingAsBlob: false

# Service configuration
service:
  enabled: true
  type: ClusterIP

# Prometheus Operator integration (requires prometheus-operator)
serviceMonitor:
  enabled: true
  interval: 30s
  scrapeTimeout: 10s

# Alternative: PodMonitor instead of ServiceMonitor
podMonitor:
  enabled: false
  interval: 30s
  scrapeTimeout: 10s

# DaemonSet mode (recommended - runs on all nodes)
daemonSet:
  enabled: true
  nodeSelector: {}
  tolerations: []

# Deployment mode (alternative to DaemonSet)
deployment:
  enabled: false
  replicas: 1
  nodeSelector: {}
  tolerations: []

# Exclude specific nodes from scheduling (by hostname)
# Takes precedence over affinity when set
excludeNodes: []
# excludeNodes:
#   - node1
#   - node2

# Custom affinity rules (only used when excludeNodes is empty)
affinity: {}

# Container resource requests and limits
resources: {}
#  limits:
#    cpu: 100m
#    memory: 128Mi
#  requests:
#    cpu: 100m
#    memory: 128Mi

Install the Helm chart:

# --create-namespace if namespace does not exist
helm install -n <namespace> <release-name> ./helm_chart \
  --create-namespace \
  --values=values.yaml

Verify Installation

Port-forward to test the metrics endpoint:

kubectl port-forward -n <namespace> svc/<release-name>-local-storage-exporter 9100:9100
curl http://localhost:9100/metrics

If ServiceMonitor is enabled and Prometheus Operator is running, metrics will automatically be scraped by Prometheus.

Tested Storage Providers

Storage Provider	StorageClass	Path on Node
openebs	openebs-hostpath	/var/openebs/local
microk8s	microk8s-hostpath	/var/snap/microk8s/common/default-storage
kind	standard	/var/local-path-provisioner
minikube	standard	/tmp/hostpath-provisioner
k3s	standard	/var/lib/rancher/k3s/storage/

Grafana Dashboard

A grafana dashboard is included as local-storage-exporter-grafana.json. You can import it into your Grafana instance to visualize the metrics collected by the exporter.