Nginx

What is a web-server

• When a user search for a page on a web-browser

  • Request is initiated by browser, leaving your LAN (Local Area Network)

    • DNS Lookup

    • TCP3 Handshake

    • SSL4 Handshake

    • HTTP and Get Request

  • Request then travel through Global Area Network

  • Then reaches to computer/server which needs to serve the request

  • Similar route in reverse direction for response

• The server/computer that serve the web-pages or provide response to requests is web-server

• Every web server has an IP address and a Domain name

• Request is served by web-server, an application is required to make a computer, a web-server

• Few examples for web-server software in market:

  • XAMPP

  • Apache

  • Nginx

  • Tornado

  • Caddy

  • Microsoft IIS

what is Ngnix

• Open source software, objective is to reduce web-page load time

• Used for:

  • Reverse proxying, Caching, Load Balancing

  • Provides HTTP server capabilities

  • Also functions as proxy server for email (IMAP, POP and SMTP)

• Mainly designed for maximum performance and stability

• Uses a non-threaded and event-driven architecture

Nginx Architecture

• Uses master-slave architecture by supporting event-driven, asynchronous, and non-blocking model

Master: Responsible for

• Reading and validating configuration

• Starting, terminating and maintaining required number of workers and number of processes within each worker

• Re-configuring without any service interruption

• Re-opening for log files

• Compile embedded for scripts

Cache Loader: responsible for

• Checking on-disc cache items and populating nginx in-memory database with the cache metadata

• Prepares nginx instances to work with files already available in the disc, arranged in specific allocated directory structure

• Cache loaded traverses the directory structure, checks cache content with the meta-data, updates relevant entry and also checks if everything is clean when system exists

Cache-Manager: responsible for

• Cache expiration and termination management

Why to use Nginx

• Easy to install and maintain

• Improves Performance

• Offers Scalability

• Reduce the wait time for users

• Load Balancing

• On the fly upgrades (no downtime when upgrading)

Nginx Installation

• Install Nginx

• Adjust Firewall

• Check your server

• Manage the Nginx Process

sudo apt-get update
sudo apt-get install nginx # install nginx
sudo ufw enable # enable firewall
nginx -v # check nginx installation status
sudo ufx app list # listing apps with firewall

sudo ufw allow "Nginx full" # to enable both encrypted and unencrypted graphic

sudo ufw status
sudo systemctl status nginx

Manage Nginx Processes, Basis Commands

sudo systemctl stop nginx # stop nginx web-server
sudo systemctl restart nginx # stop and start the service again
sudo systemctl reload nginx # if making configuration changes, reload without stop
sudo systemctl disable nginx # To not let nginx automatically start when server boots
sudo systemctl enable nginx # to enable server automatically start at boot
sudo nginx -t # to test config file

Important Directories and Files

Content

• /var/www/html: The actual web content, which by default only consists of the default Nginx page you saw earlier, is served out of the /var/www/html directory. This can be changed by altering NGINX configuration files.

Server Configuration

• /etc/nginx: The NGINX configuration directory. All of the Nginx configuration files reside here.

• /etc/nginx/nginx.conf: The main NGINX configuration file. This can be modified to make changes to the NGINX global configuration.

• /etc/nginx/sites-available/: The directory where per-site “server blocks” can be stored. NGINX will not use the configuration files found in this directory unless they are linked to the sites-enabled directory (see below). Typically, all server block configuration is done in this directory, and then enabled by linking to the other directory.

• /etc/nginx/sites-enabled/: The directory where enabled per-site “server blocks” are stored. Typically, these are created by linking to configuration files found in the sites-available directory.

• /etc/nginx/snippets: This directory contains configuration fragments that can be included elsewhere in the NGINX configuration. Potentially repeatable configuration segments are good candidates for refactoring into snippets.

Server Logs

• /var/log/nginx/access.log: Every request to your web server is recorded in this log fil unless and until NGINX is configured to do otherwise.

• /var/log/nginx/error.log: Every NGINX error will be recorded in this log only.

Configuration Settings

• Core settings of the Nginx are mainly configured in the nginx.conf file

• The configuration file is mainly structured into contexts

• Most important settings are:

  • worker_processes (How many workers, depends on number of core)

  • worker_connections (How many requests can be served simultaneously)

  • access log and error log (for debugging)

  • gzip (compression of nginx responses)

Load Balancing with Nginx

Reverse Proxying with Nginx

More Topics

Web-Application Firewalls

Cryptographic Sections - Certificates and SSL Terminations

Security Aspects Related to Web-Servers

Performance Tuning and Response Monitoring

Reference for Further Reading

• Edureka Youtube Video Lecture

• https://medium.com/adrixus/beginners-guide-to-nginx-configuration-files-527fcd6d5efd