BMW-Saver is a Kubernetes controller that automatically scales node pools of your development cluster based on work hours. It helps reduce costs by scaling down clusters during off-hours and restoring them during work hours.

• 🕑 Time-based node pool scaling
• 📆 Multiple calendar integrations for holidays and off-hours, including Google Calendar, ICS Calendar (iCloud, Outlook, etc.)
• 💾 Preserves node pool configurations and restores them during work hours
• 🔄 Auto-restore during work hours
• 🔌 Supports multiple cloud providers:
  • ✅ Google Kubernetes Engine (GKE)
  • ✅ Amazon EKS
• 📝 Live configuration updates
• 🏗️ Multi-architecture support (amd64/arm64)

• Kubernetes cluster (GKE/EKS/AKS)
• Helm 3
• AWS credentials configured, Pod Identity is recommended
• Google Calendar API credentials (optional)

helm install bmw-saver oci://ghcr.io/kezhenxu94/bmw-saver-charts/bmw-saver \
  --namespace bmw-saver \
  --create-namespace \
  --version <version>

helm install bmw-saver ./charts/bmw-saver \
  --namespace bmw-saver \
  --create-namespace \
  --set image.repository=ghcr.io/kezhenxu94/bmw-saver \
  --set image.tag=latest

Create a values.yaml file:

config:
  nodeSpecs:
    # GKE example:
    - nodePoolName: "my-gke-pool"
      cloudProvider: "gke"
      offTimeCount: 1  # Number of nodes during off-hours

    # EKS example:
    - nodePoolName: "my-eks-group"
      cloudProvider: "aws"
      offTimeCount: 1

  schedule:
    # Static schedule (required if not using Google Calendar)
    startTime: "09:00"        # Start time of work hours in a working day
    endTime: "17:00"          # End time of work hours in a working day
    timeZone: "Asia/Shanghai" # Time zone of the schedule
    workDays:                 # Work days in a week
      monday: true
      tuesday: true
      wednesday: true
      thursday: true
      friday: true
      saturday: false
      sunday: false

    # Optional Google Calendar integration
    googleCalendar:
      calendarId: "your-calendar-id@group.calendar.google.com"
      credentialsPath: "/etc/google/credentials.json"
      offTimeEvents: "<my name> Public Holiday"  # Search query for off-time events
      syncInterval: "1h"                        # How often to sync calendar
      cacheDays: 7                             # Days of events to cache

    # Optional ICS Calendar integration
    icsCalendar:
      url: "https://calendars.icloud.com/holidays/cn_zh.ics"  # Public holiday calendar
      workDayPatterns:                                        # Match work day events
        - ".*（班）"                                           # You know, Chinese special work days
      holidayPatterns:                                        # Match holiday events
        - ".*（休）"                                           # Chinese holidays
      syncInterval: "1h"                                      # How often to sync calendar

# Google Calendar credentials secret
googleCalendar:
  # Set to true to create a secret for Google Calendar credentials
  enabled: false
  # Base64 encoded credentials.json content
  # You can encode your file using: base64 -w 0 credentials.json
  credentials: ""
  # Or specify an existing secret name
  existingSecret: ""
  # Key in the secret that contains the credentials
  credentialsKey: "credentials.json"

env:
  # Required for AWS
  - name: EKS_CLUSTER_NAME
    value: "my-cluster-name"

Then install with your values:

helm install bmw-saver ./charts/bmw-saver \
  --namespace bmw-saver \
  --create-namespace \
  -f values.yaml

BMW-Saver determines work hours through:

1. During work hours:

   • Must satisfy ALL configured schedules:
     • Within static schedule time range (if configured)
     • No matching off-time events in Google Calendar (if configured)
   • Restores node pools to their saved configurations
   • Maintains autoscaling settings if previously enabled

2. During off-hours (any schedule indicates off-hours):

   • Scales down node pools to specified offTimeCount
   • Safely drains nodes before scaling down
   • Preserves original configuration in ConfigMaps

To use Google Calendar integration:

1. Create a Google Cloud project and enable the Calendar API
2. Create a service account and download credentials.json
3. Share your calendar with the service account email
4. Base64 encode your credentials.json:

   base64 credentials.json > credentials.base64

5. Configure the calendar settings in values.yaml
6. Set offTimeEvents to match your holiday/off-time event titles

To use BMW-Saver with Amazon EKS:

1. Ensure AWS credentials are properly configured with EKS permissions
2. Set the required environment variables:

   env:
     - name: EKS_CLUSTER_NAME
       value: "your-cluster-name"  # Required for EKS

3. Configure your node groups in values.yaml:

   config:
     nodeSpecs:
       - nodePoolName: "my-eks-group"
         cloudProvider: "aws"
         offTimeCount: 1

• Go 1.23+
• Docker
• Kubernetes cluster (GKE/EKS/AKS)
• Helm 3

# Build binary
make build

# Build Docker image
make docker-build

# Build and push multi-arch Docker image
make docker-push HUB=ghcr.io/your-username

# Run locally
go run main.go --config config.yaml --log-level debug

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

If this project helps you save money, please consider sponsoring me to support the development.

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.