nginx load balancing configuration for web sockets

Question

I am configuring Nginx to redirect incoming web socket requests to two different servers, but every time I get 404.

My Nginx configuration in loadbalancer.conf file in /etc/nginx/conf.d/ folder look like this:

upstream websocket {
    server localhost:5050; //web socket server1 running here
    server localhost:8080; //web socket server2 running here
}
server {
    listen      4141;
    server_name localhost:4141;

    location / {
        proxy_pass http://websocket;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Host $host;
        proxy_set_header Connection "upgrade";
    }
}

When I am hitting web socket servers directly (URL: ws://localhost:8080/app/socket/user1) then the request are working fine but when I am going through Nginx (URL: ws://localhost:4141/app/socket/user1) then the requests are not delivering to any of the web socket servers.

Update:

1. I have tried to change the proxy_pass setting to directly the server1 (localhost:5050) then also the request is not going through.
2. Nginx access log says the following error:

::1 - - [09/Jan/2023:10:57:07 +0530] "GET /app/socket/user1 HTTP/1.1" 404 197 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.90 Safari/537.36"

Can someone please answer

1. What is wrong with the configuration?
2. Does Nginx provide more detailed logs, where can I check them?

Answer 1

You can use ip_hash configuration for nginx up_stream blo

upstream websocket {
ip_hash;
server localhost:5050; //web socket server1 running here
server localhost:8080; //web socket server2 running here
}
server {
listen      4141;
server_name localhost:4141;

location / {
    proxy_pass http://websocket;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Host $host;
    proxy_set_header Connection "upgrade";
}