Blue-Green Deployment

Table of Contents

• Overview
• When to Use
• Quick Start
• Reference Guides
• Best Practices

Overview

Deploy applications using blue-green deployment patterns to maintain two identical production environments, enabling instant traffic switching and rapid rollback capabilities.

When to Use

• Zero-downtime releases
• High-risk deployments
• Complex application migrations
• Database schema changes
• Rapid rollback requirements
• A/B testing with environment separation
• Staged rollout strategies

Quick Start

Minimal working example:

# blue-green-setup.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: blue-green-config
  namespace: production
data:
  switch-traffic.sh: |
    #!/bin/bash
    set -euo pipefail

    CURRENT_ACTIVE="${1:-blue}"
    TARGET="${2:-green}"
    ALB_ARN="arn:aws:elasticloadbalancing:us-east-1:123456789012:loadbalancer/app/myapp-alb/1234567890abcdef"

    echo "Switching traffic from $CURRENT_ACTIVE to $TARGET..."

    # Get target group ARNs
    BLUE_TG=$(aws elbv2 describe-target-groups \
      --load-balancer-arn "$ALB_ARN" \
      --query "TargetGroups[?Tags[?Key=='Name' && Value=='blue']].TargetGroupArn" \
      --output text)

    GREEN_TG=$(aws elbv2 describe-target-groups \
      --load-balancer-arn "$ALB_ARN" \
// ... (see reference guides for full implementation)

Reference Guides

Detailed implementations in the references/ directory:

Guide	Contents
Blue-Green with Load Balancer	Blue-Green with Load Balancer
Blue-Green Rollback Script	Blue-Green Rollback Script
Monitoring and Validation	Monitoring and Validation

Best Practices

✅ DO

• Follow established patterns and conventions
• Write clean, maintainable code
• Add appropriate documentation
• Test thoroughly before deploying

❌ DON'T

• Skip testing or validation
• Ignore error handling
• Hard-code configuration values