Zero-Downtime Blue-Green Deployments on AWS EKS: Infrastructure as Code with Terraform and GitOps

# AWS EKS Cluster Definition with Strict Security Group Enforcement
module "eks_cluster" {
  source  = "terraform-aws-modules/eks/aws"
  version = "~> 20.0"

  cluster_name    = "xiyor-production-eks"
  cluster_version = "1.30"

  cluster_endpoint_public_access  = true
  cluster_endpoint_private_access = true

  vpc_id     = module.vpc.vpc_id
  subnet_ids = module.vpc.private_subnets

  # Managed Node Groups with Auto-Scaling Policies
  eks_managed_node_groups = {
    core_nodes = {
      min_size     = 3
      max_size     = 10
      desired_size = 4

      instance_types = ["m6i.xlarge"]
      capacity_type  = "ON_DEMAND"

      labels = {
        role = "application-workloads"
      }
    }
  }

  # Enable OIDC provider for fine-grained Pod IAM roles
  enable_irsa = true
}

apiVersion: argoproj.io/v1alpha1
kind: Rollout
metadata:
  name: xiyor-core-service
  namespace: production
spec:
  replicas: 5
  strategy:
    blueGreen:
      activeService: xiyor-core-active
      previewService: xiyor-core-preview
      autoPromotionEnabled: false
      autoPromotionSeconds: 300
      antiAffinity:
        preferredDuringSchedulingIgnoredDuringExecution:
          weight: 100
  template:
    metadata:
      labels:
        app: xiyor-core-service
    spec:
      containers:
      - name: app
        image: 123456789012.dkr.ecr.us-east-1.amazonaws.com/xiyor-core:v2.4.1
        ports:
        - containerPort: 8080
        readinessProbe:
          httpGet:
            path: /healthz
            port: 8080
          initialDelaySeconds: 5
          periodSeconds: 3