Distributed Deployment

To deploy your application to multiple servers, You need to change the app configuration to support distributed deployment.

## Session sharing

To enable session sharing between servers, you need to configure your application to use a shared session store.

You can use a Redis server to store session data, then configure your application to use it.

**.env**

```bash
YAO_SESSION_STORE=redis
YAO_SESSION_HOST=your-redis-server-ip
YAO_SESSION_PORT=yout-redis-server-port
YAO_SESSION_PASSWORD=your-redis-server-password
YAO_SESSION_DB=5 # Redis database number
```

Make sure each server has access to the Redis server and the same session configuration.

## Database Connection

If you're using a database, you need to configure the database connection for each server.

**.env**

```bash
YAO_DB_DRIVER=mysql
YAO_DB_PRIMARY="webuser:webpass@tcp(127.0.0.1:3306)/website?charset=utf8mb4&parseTime=True&loc=Local"
YAO_DB_SECONDARY="webuser:webpass@tcp(127.0.0.1:3306)/website?charset=utf8mb4&parseTime=True&loc=Local" # Optional, Read-Replica
```

Make sure each server has access to the database server and the same database configuration.

## Data Synchronization

If your application writes data to the filesystem, you need to synchronize the data between servers.

or you can use a shared storage solution like NFS, GlusterFS, or AWS EFS to store the data.

**.env**

```bash
YAO_DATA_ROOT=/path/to/shared/storage
```

## Load Balancer

To distribute traffic across multiple servers, you can use a load balancer.

A load balancer evenly distributes incoming requests to various servers using different algorithms such as Round-Robin, Least Connections, or IP Hash.

You can choose between a hardware load balancer or a software-based solution like NGINX, HAProxy, or AWS ELB.

**NGINX Configuration**

```nginx
http {
    upstream app_servers {
        # List of your application servers
        server app_server_1_ip:5099;
        server app_server_2_ip:5099;
        server app_server_3_ip:5099;

        # Optional: configure load balancing algorithms
        # least_conn; # Least connections method
        # ip_hash;    # IP hash method for session persistence
    }

    server {
        listen 80;  # Port the load balancer will listen on

        server_name your-domain.com;  # Your domain or IP address

        location / {
            proxy_pass http://app_servers;  # Forward traffic to app servers
            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;
        }
    }
}
```