How do you configure NGINX as a reverse proxy with load balancing, health checks, and SSL termination for a microservices architecture?

upstream api_backend {
    least_conn;
    server 10.0.1.10:8080 max_fails=3 fail_timeout=30s;
    server 10.0.1.11:8080 max_fails=3 fail_timeout=30s;
    server 10.0.1.12:8080 max_fails=3 fail_timeout=30s;
    server 10.0.1.13:8080 backup;  # Only used when others fail
    
    keepalive 32;  # Connection pooling to backends
}

server {
    listen 443 ssl http2;
    server_name api.example.com;
    
    # SSL configuration
    ssl_certificate     /etc/nginx/ssl/cert.pem;
    ssl_certificate_key /etc/nginx/ssl/key.pem;
    ssl_protocols       TLSv1.2 TLSv1.3;
    ssl_ciphers         HIGH:!aNULL:!MD5;
    ssl_session_cache   shared:SSL:10m;
    ssl_session_timeout 10m;
    
    # Security headers
    add_header Strict-Transport-Security "max-age=31536000" always;
    add_header X-Content-Type-Options nosniff;
    
    location /api/ {
        proxy_pass http://api_backend;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        
        # Timeouts
        proxy_connect_timeout 5s;
        proxy_read_timeout 30s;
        proxy_send_timeout 10s;
        
        # Connection reuse
        proxy_http_version 1.1;
        proxy_set_header Connection "";
    }
}

# Redirect HTTP to HTTPS
server {
    listen 80;
    server_name api.example.com;
    return 301 https://$host$request_uri;
}