Kubernetes Custom Autoscaler Controller

Overview

A custom Kubernetes controller that implements specialized autoscaling logic for deployments. Built with Go and deployed via Terraform to AWS EKS.

Features

• Monitors deployment metrics
• Implements custom scaling algorithms
• Integrates with AWS EKS
• Terraform-managed infrastructure

Prerequisites

• Docker
• AWS CLI
• Terraform 1.5+
• Go 1.21+
• kubectl

Deployment Workflow

1. Build Docker Image

docker build -t <your-registry>/custom-autoscaler:v1.0 .

2. Push to Container Registry

# For Docker Hub:
docker push <your-registry>/custom-autoscaler:v1.0

# For Amazon ECR:
aws ecr get-login-password --region <region> | docker login --username AWS --password-stdin <account-id>.dkr.ecr.<region>.amazonaws.com
docker tag custom-autoscaler:v1.0 <account-id>.dkr.ecr.<region>.amazonaws.com/custom-autoscaler:v1.0
docker push <account-id>.dkr.ecr.<region>.amazonaws.com/custom-autoscaler:v1.0

3. Deploy Infrastructure

cd terraform
terraform init
terraform apply -var="controller_image=<your-registry>/custom-autoscaler:v1.0"

4. Verify Deployment

kubectl get pods -l app=custom-autoscaler
kubectl logs deployment/custom-autoscaler

Architecture

graph TD
    A[Custom Controller] -->|Monitors| B(Deployments)
    B --> C{Scaling Needed?}
    C -->|Yes| D[Scale Deployment]
    C -->|No| B

Clean Up

terraform destroy
docker image rm <your-registry>/custom-autoscaler:v1.0

Configuration Options

Environment Variable	Description	Default
SCALE_THRESHOLD	CPU% to trigger scale	80
CHECK_INTERVAL	Metrics check frequency	30s

**4. Terraform Updates**
In your controller module (`terraform/modules/controller/main.tf`):
```hcl
resource "kubernetes_deployment" "controller" {
  # ... existing config ...
  
  spec {
    template {
      spec {
        container {
          image = var.controller_image
          # Add environment variables if needed
          env {
            name  = "SCALE_THRESHOLD"
            value = "75"
          }
        }
      }
    }
  }
}

4. Workflow Summary

1. Develop Controller

   • Edit controller.go
   • Test locally: go run controller.go

2. Build & Push Image

   docker build -t <your-registry>/custom-autoscaler:v1.1 .
   docker push <your-registry>/custom-autoscaler:v1.1

3. Update Infrastructure

   cd terraform
   terraform apply -var="controller_image=<your-registry>/custom-autoscaler:v1.1"

4. Monitor Operations

   kubectl logs -f deployment/custom-autoscaler

Key Notes:

• The controller runs as a Deployment in your EKS cluster
• RBAC rules (from previous config) ensure proper permissions
• Image registry can be Docker Hub, ECR, or any private registry
• Version tagging helps manage updates
• The Terraform module completely manages the controller lifecycle

This setup provides a complete CI/CD pipeline for your custom controller from development to production deployment.