Configure Nginx: Load balancing and reverse proxy

nginx.conf

### host file under sites-available ###


# The upstream module is the link between Node.js and Nginx.
# Upstream is used for proxying requests to other servers.
# All requests for / get distributed between any of the servers listed.
upstream app_nodeapp1 {

  # Set up multiple Node.js webservers for Load balancing.
  # max_fails refers to number of failed attempts
  # before server is considered inactive.
  # weight priorities traffic to server. Ex. weight=2 will recieve
  # twice as much traffic as server with weight=1

  server 127.0.0.1:3000 max_fails=0 fail_timeout=10s weight=1;
  # server <your server ip>:3001 max_fails=0 fail_timeout=10s weight=1;
  # server <your server ip>:3002 max_fails=0 fail_timeout=10s weight=1;
  # server <your server ip>:3003 max_fails=0 fail_timeout=10s weight=1;
 
  # Send visitors back to the same server each time.
  ip_hash;
 
  # Enable number of keep-alive connections.
  keepalive 512;
}
 
server {
  listen 80;
  listen [::]:80 default_server ipv6only=on;
 
  # Index files.
  index index.html;
 
  # Domain names.
  # Make sure to set the A Record on your domain's DNS settings to your server's IP address.
  # You can test if was set properly by using the `dig` command: dig yourdomain.com
  server_name nodeapp1.com www.nodeapp1.com;
 
  # Timeout for closing keep-alive connections.
  keepalive_timeout 10;
  
  # Enable gzip compression.
  gzip on;
  gzip_http_version 1.1;
  gzip_vary on;
  gzip_comp_level 6;
  gzip_proxied any;
  gzip_buffers 16 8k;
  gzip_disable "MSIE [1-6]\.(?!.*SV1)";
  
  # Max upload size.
  # client_max_body_size 16M;
 
  # Change access and error log files.
  # access_log /var/log/nginx/yourdomain.com/access.log;
  # error_log /var/log/nginx/yourdomain.com/error.log;
 
  # Custom error page.
  # error_page 404 maintenance.html;
  # error_page 500 502 503 504 maintenance.html;
  
  # location /maintenance.html {
  #  root /var/www;
  # }
 
  location / {
    # Set this to your upstream module.
    proxy_pass http://app_nodeapp1;

    # Proxy headers.
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $host;
    proxy_set_header X-NginX-Proxy true;

    # To handle websocket requests
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_cache_bypass $http_upgrade;
    proxy_http_version 1.1;
    proxy_redirect off;

    # Go to next upstream after if server down.
    proxy_next_upstream error timeout http_500 http_502 http_503 http_504;
    proxy_connect_timeout 5s;
    # Gateway timeout.
    proxy_read_timeout 20s;
    proxy_send_timeout 20s;
    # Buffer settings.
    proxy_buffers 8 32k;
    proxy_buffer_size 64k;
  }
 
  # Enable caching of static files.
  # location ~* \.(css|js|gif|jpe?g|png)$ {
  #  expires 168h;
  #  add_header Pragma public;
  #  add_header Cache-Control "public, must-revalidate, proxy-revalidate";
  # }
  
  # Don't cache html files.
  # location ~* \.html$ {
  #  expires -1;
  # }
}