app1/nginx/nginx.conf

worker_processes 1;

events { worker_connections 1024; }

http {

    sendfile on;

    upstream app {
        server app:3001;
        server prometheus:9090;
        server grafana:3000;
    }

    server {
        listen 80;

        location / {
            proxy_pass http://app;
        }

        # location /prometheus {
        #     proxy_pass http://prometheus;
        # }        

        # location /grafana {
        #     proxy_pass http://grafana;
        # }
    }
}