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PVC Chonker

PVC Chonker

PVC Chonker is a cloud-agnostic Kubernetes operator for automatic PVC expansion. Works with any CSI-compatible storage without external dependencies.

What is PVC Chonker?​

PVC Chonker automatically expands Persistent Volume Claims (PVCs) when they reach capacity thresholds, preventing storage-related outages and reducing manual intervention.

Key Features​

  • Cloud Agnostic - Works with any CSI-compatible storage
  • No External Dependencies - Self-contained operation
  • Annotation-Based - Simple configuration through Kubernetes annotations
  • Policy-Based - Advanced configuration through PVCPolicy custom resources
  • Safety Features - Cooldown protection and resize safety checks
  • Inode Monitoring - Monitors both storage and inode usage

Why PVC Chonker?​

Problems It Solves​

  • Storage Outages - Prevents applications from failing due to full disks
  • Manual Intervention - Eliminates need for manual PVC expansion
  • Capacity Planning - Reduces operational overhead of storage management
  • Multi-Cloud - Works consistently across different cloud providers

Benefits​

  • Proactive - Expands before reaching 100% capacity
  • Configurable - Flexible thresholds and expansion policies
  • Safe - Built-in protections against rapid expansions
  • Observable - Comprehensive metrics and logging

Quick Start​

Installation​

# Add Helm repository
helm repo add logiciq https://logiciq.github.io/helm-charts
helm repo update

# Install PVC Chonker
helm install pvc-chonker logiciq/pvc-chonker -n pvc-chonker-system --create-namespace

Basic Usage​

Annotate your PVC to enable auto-expansion:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-pvc
  annotations:
    pvc-chonker.io/enabled: "true"
    pvc-chonker.io/threshold: "80%"
    pvc-chonker.io/increase: "20%"
spec:
  accessModes: [ReadWriteOnce]
  storageClassName: your-expandable-storage-class
  resources:
    requests:
      storage: 10Gi

Core Concepts​

Thresholds​

  • Storage Threshold - Percentage of storage used before expansion
  • Inode Threshold - Percentage of inodes used before expansion
  • Dual Monitoring - Expands when either threshold is reached

Expansion Policies​

  • Percentage-Based - Increase by percentage (e.g., "20%")
  • Fixed Amount - Increase by fixed size (e.g., "5Gi")
  • Minimum Scale-Up - Ensure meaningful increases
  • Maximum Size - Prevent unlimited growth

Safety Features​

  • Cooldown Period - Prevents rapid successive expansions
  • Resize Detection - Skips PVCs currently being resized
  • Size Validation - Respects maximum size limits

Configuration Hierarchy​

PVC Chonker uses a priority-based configuration system where settings are applied in the following order (highest to lowest priority):

1. PVC Annotations (Highest Priority)​

Direct annotations on individual PVCs always take precedence:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-pvc
  annotations:
    pvc-chonker.io/enabled: "true"     # Overrides all other settings
    pvc-chonker.io/threshold: "90%"     # Overrides policy/group/global
    pvc-chonker.io/increase: "50%"      # Overrides policy/group/global
spec:
  # ... PVC spec

2. PVCGroup Template (Medium-High Priority)​

When a PVC matches a PVCGroup selector, group template settings apply:

apiVersion: pvc-chonker.io/v1alpha1
kind: PVCGroup
metadata:
  name: database-group
spec:
  selector:
    matchLabels:
      app: database
  template:
    enabled: true
    threshold: "80%"    # Applied if no PVC annotation
    increase: "25%"     # Applied if no PVC annotation

3. PVCPolicy Template (Medium Priority)​

Namespace-scoped policies apply to matching PVCs:

apiVersion: pvc-chonker.io/v1alpha1
kind: PVCPolicy
metadata:
  name: default-policy
spec:
  selector:
    matchLabels:
      tier: storage
  template:
    enabled: true
    threshold: 75.0     # Applied if no annotation or group
    increase: "20%"     # Applied if no annotation or group

4. Global Configuration (Low Priority)​

Operator-level defaults from flags/environment variables:

# Command line flags or environment variables
--default-threshold=70
--default-increase="15%"
--default-cooldown="10m"

5. Built-in Defaults (Lowest Priority)​

Hardcoded fallback values when no other configuration exists:

  • enabled: false
  • threshold: 80%
  • increase: 10%
  • cooldown: 15m
  • min-scale-up: 1Gi

Priority Resolution Example​

Given this configuration:

# Global: threshold=70%, increase=15%
# PVCPolicy: threshold=75%, increase=20%
# PVCGroup: threshold=80%, increase=25%
# PVC Annotation: threshold=90%

# Final effective configuration:
# threshold: 90% (from PVC annotation - highest priority)
# increase: 25% (from PVCGroup - highest available)
# cooldown: 15m (from global default)

Key Points:

  • PVC annotations always win
  • PVCGroup templates override PVCPolicy templates
  • Only specified fields override lower priorities
  • Unspecified fields fall through to next priority level

Configuration Methods​

1. Annotations (Simple)​

Direct configuration on individual PVCs:

annotations:
  pvc-chonker.io/enabled: "true"
  pvc-chonker.io/threshold: "85%"
  pvc-chonker.io/increase: "25%"

2. PVCPolicy (Advanced)​

Centralized policies for multiple PVCs:

apiVersion: pvc-chonker.io/v1alpha1
kind: PVCPolicy
metadata:
  name: database-policy
spec:
  selector:
    matchLabels:
      workload: database
  template:
    enabled: true
    threshold: 85.0
    increase: "25%"

3. PVCGroup (Coordinated)​

Synchronized expansion across related PVCs:

apiVersion: pvc-chonker.io/v1alpha1
kind: PVCGroup
metadata:
  name: elasticsearch-cluster
spec:
  selector:
    matchLabels:
      app: elasticsearch
  coordinationPolicy: "largest"

Getting Started​

Use Cases​

Advanced Features​

Community​