Nginx

By Known-Space -

What is a Web Server?

A web server is software and hardware that uses HTTP (Hypertext Transfer Protocol) and other protocols to respond to client requests made over the World Wide Web. The main job of a web server is to display website content through storing, processing, and delivering webpages to users. Besides HTTP, web servers also support SMTP (Simple Mail Transfer Protocol) and FTP (File Transfer Protocol), used for email, file transfer, and storage.

Web servers are used in web hosting or the hosting of data for websites and web-based applications -- or web applications.

How do web servers work?

Web server software is accessed through the domain names of websites and ensures the delivery of the site's content to the requesting user. The software side is also comprised of several components, with at least an HTTP server. The HTTP server is able to understand HTTP and URLs. As hardware, a web server is a computer that stores web server software and other files related to a website, such as HTML documents, images, and JavaScript files.

When a web browser, like Google Chrome or Firefox, needs a file that's hosted on a web server, the browser will request the file by HTTP. When the request is received by the web server, the HTTP server will accept the request, find the content, and send it back to the browser through HTTP.

More specifically, when a browser requests a page from a web server, the process will follow a series of steps. 

1.    First, a person will specify a URL in a web browser's address bar. 

2.    The web browser will then obtain the IP address of the domain name -- either translating the URL through DNS (Domain Name System) or by searching in its cache. This will bring the browser to a web server. 

3.    The browser will then request the specific file from the webserver by an HTTP request. The web server will respond, sending the browser the requested page, again, through HTTP. 

4.    If the requested page does not exist or if something goes wrong, the web server will respond with an error message. 

5.    The browser will then be able to display the webpage.

Multiple domains also can be hosted on one web server.

Examples of web server use

Web servers often come as part of a larger package of the internet- and intranet-related programs that are used for:

·        sending and receiving emails;

·        downloading requests for File Transfer Protocol (FTP) files;

·        building and publishing webpages.

 

Common and top web server software on the market

There are a number of common web servers available, some including:

·        Apache HTTP Server. Developed by Apache Software Foundation, it is a free and open-source web server for Windows, Mac OS X, Unix, Linux, Solaris, and other operating systems; it needs the Apache license.

·        Microsoft Internet Information Services (IIS). Developed by Microsoft for Microsoft platforms; it is not open-sourced but widely used.

·        Nginx. A popular open-source web server for administrators because of its light resource utilization and scalability. It can handle many concurrent sessions due to its event-driven architecture. Nginx also can be used as a proxy server and load balancer.

·        Lighttpd. A free web server that comes with the FreeBSD operating system. It is seen as fast and secure while consuming less CPU power.

·        Sun Java System Web Server. A free web server from Sun Microsystems that can run on Windows, Linux and Unix. It is well-equipped to handle medium to large websites.

 What is Nginx?

Nginx Architecture

Nginx uses Master-Slave architecture by supporting event-driven, asynchronous, and non-blocking model.


Why should we use Nginx?


Configuration Settings

The core settings of NGINX are mainly configured in the Nginx.conf file. The configuration file is mainly structured into contexts(event context and Http context).

worker_process: Settings that define the number of worker_process that NGINX use. The number will be the number of CPU cores.

worker_connections: Maximum number of simultaneous connections for each worker_process.

access_log & error_log: These are the files that Nginx uses to log any errors and access attempts. These loges are used for debugging and troubleshooting.

gzip: These are settings for gzip compression of Nginx responses.

How to install NGINX?



1. Open the terminal on Ubuntu or Debian and run the following command to ensure that all packages on the OS are up to date:

sudo apt-get update  


2. Since Nginx is available in the default repository of Debian or Ubuntu, it is possible to install it from these repositories using the apt packaging system.

sudo apt-get install nginx




3. Once it is done, use the following command to see the process for the webserver in a running state.

ps -ef | grep nginx




4. Adjusting the firewall to access Nginx: For accessing the Nginx from the web server, we have to allow access to the services from outside. To see the list of profiles available to allow from the firewall, use the following command:

sudo ufw app list


Here,

Nginx Full: It allows both ports 80 and 443.

Nginx HTTP: It allows only port 80.

Nginx HTTPS: It allows only port 443.

To allow both ports HTTP 80 and HTTPS 443 then use the following command:

sudo ufw allow 'Nginx Full' 

To allow only Nginx HTTP port 80 use the following command:

sudo ufw allow 'Nginx HTTP'  

To allow only Nginx HTTPS port 443, use the following command:

sudo ufw allow 'Nginx HTTPS' 

5. By default, after the installation of Ubuntu, the Nginx starts automatically and we can check the status of the Nginx with the help of the following command:

systemctl status nginx 


Manage the NGINX Process

Now that you have your web server up and running, we can go over some basic management commands.

To stop your web server

sudo systemctl stop nginx

To start the web server when it is stopped

sudo systemctl start nginx

To stop and then start the service again

sudo systemctl restart nginx

If you are simply making configuration changes, NGINX can often reload without dropping connections. To do this, this command can be used

sudo systemctl reload nginx

By default, NGINX is configured to start automatically when the server boots. If this is not what you want, you can disable this behavior by typing:

sudo systemctl disable nginx

To re-enable the service to start up at boot

sudo systemctl enable nginx

To test your config file

sudo nginx -t

 

Important NGINX Files and Directories

So once you get to know how to manage the service itself, you should take a few minutes to familiarize yourself with a few 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 file unless and until NGINX is configured to do otherwise.

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

Configure NGINX to serve your website

You’ll need to tell NGINX about your website and how to serve it.

cd into /etc/nginx/. This is where the NGINX configuration files are located.

The two directories we are interested in are sites-available and sites-enabled.

·        sites-available contains individual configuration files for all of your possible static websites.

·        sites-enabled contains links to the configuration files that NGINX will actually read and run.

Now, cd into /etc/nginx/sites-enabled and edit default file using nano or vi as per your choice to following :

server {
    listen 80 default_server;
    listen [::]:80 default_server; 
    root /var/www/html;  
    index index.html; 
    server_name _;  

    location / {
       try_files $uri $uri/ =404;
     }
}

The above code is for:

·        Deliver files from the folder /var/www/html or this can be a path to your index.html.

·        The main index page is called index.html.

·        Requests that are requesting should be served by this server block.

Now, if you are about to restart NGINX you should see your site!

sudo systemctl restart nginx

Configure NGINX to serve your backend

You’ll need to tell NGINX about your website and how to serve it.

cd into /etc/nginx/. This is where the NGINX configuration files are located.

The two directories we are interested in are sites-available and sites-enabled.

·        sites-available contains individual configuration files for all of your possible static websites.

·        sites-enabled contains links to the configuration files that NGINX will actually read and run.

Now, cd into /etc/nginx/sites-enabled and edit default file using nano or vi as per your choice to following :

server {
    listen 80 default_server
    listen [::]:80 default_server; 
    root /var/www/html;  
    index index.html; 
    server_name _;  

    location / {
       try_files $uri $uri/ =404;
    }

    location /api/ {
           proxy_pass http://localhost:8080/;
           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;
    }

}

What does the above code means

·        On /api route back-end can be accessed which is a link to out local-host process in the port 8080

If you have gone through the entire blog, you might have understood everything on how to install Nginx and configure it for your usage. The blog has also given you information about creating a reverse proxy and creating redirects.

Configure NGINX to serve your Image folder

cd into /etc/nginx/sites-enabled and edit default file using nano or vi as per your the choice to following:

server {
    listen 80 default_server;
    listen [::]:80 default_server; 
    root /var/www/html;  
    index index.html; 
    server_name _;  

    location / {
       try_files $uri $uri/ =404;
    }
    location /api/ {
           proxy_pass http://localhost:8080/;
           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 /images {
           alias uploads/images/;
    }
}

What does the above code means

·        On /images route images can be accessed which is a link to instance folder uploads/images. It will point to all images in the images folder.

Conclusion

If you have gone through the entire blog, you might have understood everything on how to install Nginx and configure it for your usage.

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