Load Balancing

# Layer 4 Load Balancer Configuration (HAProxy example)
frontend tcp_front
    bind *:3306
    mode tcp
    default_backend mysql_servers

backend mysql_servers
    mode tcp
    balance leastconn
    option tcp-check
    server mysql1 10.0.1.10:3306 check
    server mysql2 10.0.1.11:3306 check
    server mysql3 10.0.1.12:3306 check

# Layer 7 Load Balancer Configuration (NGINX example)
upstream api_v1 {
    least_conn;
    server api1.example.com:8080;
    server api2.example.com:8080;
}

upstream api_v2 {
    least_conn;
    server api3.example.com:8080;
    server api4.example.com:8080;
}

server {
    listen 443 ssl;
    server_name api.example.com;

    # Route based on URL path
    location /v1/ {
        proxy_pass http://api_v1;
    }

    location /v2/ {
        proxy_pass http://api_v2;
    }

    # Health check endpoint
    location /health {
        access_log off;
        return 200 "healthy\n";
    }
}

# GSLB Configuration (Conceptual)
# DNS-based global load balancing

# Route 53 Geolocation Routing Policy
resource "aws_route53_record" "api_us" {
  zone_id = aws_route53_zone.main.zone_id
  name    = "api.example.com"
  type    = "A"
  
  geolocation_routing_policy {
    continent = "NA"
  }
  
  alias {
    name    = aws_lb.us_east.dns_name
    zone_id = aws_lb.us_east.zone_id
  }
  
  health_check_id = aws_route53_health_check.us.id
}

resource "aws_route53_record" "api_eu" {
  zone_id = aws_route53_zone.main.zone_id
  name    = "api.example.com"
  type    = "A"
  
  geolocation_routing_policy {
    continent = "EU"
  }
  
  alias {
    name    = aws_lb.eu_west.dns_name
    zone_id = aws_lb.eu_west.zone_id
  }
  
  health_check_id = aws_route53_health_check.eu.id
}