Two locations not working in nginx for MERN application - nginx

Question

I have nginx configuration like this:
server {
listen 80 default_server;
listen[::]:80 default_server;
server_name _;
root /var/www/html/ericwu-trademarket/frontend/build;
location /backend/ {
proxy_pass http://localhost:8000; #backend in node js
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;
}
location / {
try_files $uri /index.html; #front end in react js
}
}
the front end is running properly. But by running backend like this http://server-ip-address/backend it is showing cannot get /backend/.
Where might I be mistaken?

Answer 1

Check UFW port Allow in server
Check status of UFW:
sudo ufw status verbose
If not show 8000/tcp as a Allow then allow it:
sudo ufw allow 8000

Answer 2

Obviously you are trying to use Websokets.
When it comes to best practices, is better to have the backend services defined inside an upstream definition. You are trying to proxy requests to "localhost:8000" but localhost translates to ip 127.0.0.1. If that is not the ip address of the nodejs app, then is pretty normal that your config won't work.
Nginx expects a fully qualified domain name (FQDN), or ip addresses list of backend servers to work properly.
That being said, your config should be:
http {
upstream backend_server {
#least_conn; #Loadbalancing method in case you want to use multiple backends
#ip_hash;
server backend1.example.com:8000; #or IP address
}
server {
server_name _;
listen 80 default_server;
listen[::]:80 default_server;
root /var/www/html/ericwu-trademarket/frontend/build;
location / {
try_files $uri /index.html;
}
location /backend {
proxy_pass http://backend_server;
proxy_redirect off;
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;
# WebSocket specific
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
# For long running HTTP requests, don't buffer up the
# response from origin servers but send them directly to the client.
proxy_buffering off;
}
}
}