Load-balancing-Socket.Io-NodeJs

Load balancing Socket.Io NodeJs - Solution 1

There are multiple reasons we should not use sticky session. So here is solution, but we will miss what socketio offers.

Dependencies

• dotenv
• express
• redis
• socket.io
• socket.io-redis

Solution 2

We are using Redis and socket.io-redis adapter to loadbalance, which works perfectly. But on Socket.io by default, a long-polling connection is established first, then upgraded to “better” transports (like WebSocket). With the above method, we are not getting the benefits of using socket.io over raw websocket.

Works With

• Devices supporting websocket.

I have discussed about the solution here, Load Balancing Node.js Application #Socket.io

We have solution_2.conf Nginx configuration file, which will loadbalance the requests comming on http://socket.node to http://localhost:4010 and http://localhost:4011.

So, to first to make socket.node host available add

127.0.1.3 socket.node

on /etc/hosts, just as on the etc-hosts file

Then create solution_2.conf (or any name) and add this content there

upstream swbackend {
    server localhost:4010;
    server localhost:4011;
}

server { 
    server_name socket.node;
    location / {
        proxy_pass http://swbackend;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass
        $http_upgrade;
    }
}

just as in solution_2.conf file.

Now, let’s start the node server on two port.

first with port 4010

second with port 4011

Socket.io: In that case (transports: [ 'websocket' ]), you should maybe consider using raw WebSocket, or a thin wrapper like robust-websocket.