LEMP installation : Ubuntu 20.04

This guide demonstrates how to install a LEMP stack on an Ubuntu 20.04 server. The Ubuntu operating system takes care of the first requirement. We will describe how to get the rest of the components up and running.

What is LEMP ?

The LEMP software stack serves dynamic web pages and web applications written in PHP. This is an acronym that describes a Linux operating system, with an Nginx (pronounced like “Engine-X”) web server. The MySQL database  stores backend data and PHP handles the dynamic processing.

Prerequisites

In order to complete this tutorial, you will need access to an Ubuntu 20.04 server as a regular, non-root sudo user, and a firewall enabled on your server. To set this up, you can follow our initial server setup guide for Ubuntu 20.04.

Step 1 – Installing the Nginx Web Server

In order to display web pages to our site visitors, we are going to employ Nginx, a high-performance web server. We’ll use the apt package manager to obtain this software.

Since this is our first time using apt for this session, start off by updating your server’s package index. Following that, you can use apt install to get Nginx installed:

When prompted, enter Y to confirm that you want to install Nginx. The Nginx web server will be active and running on your Ubuntu 20.04 server, after the installation is complete.

If you have the ufw firewall enabled, as recommended in our initial server setup guide, you will need to allow connections to Nginx. Nginx registers a few different UFW application profiles upon installation. To check which UFW profiles are available, run:

Available applications:
  Nginx Full
  Nginx HTTP
  Nginx HTTPS
  OpenSSH

You should enable the most restrictive profile. It will still allow the traffic you need. Since you haven’t configured SSL for your server in this guide, you will only need to allow regular HTTP traffic on port 80.

Enable this by typing:

You can verify the change by running:

This command’s output will show that HTTP traffic is now allowed:

Status: active

To                         Action      From
--                         ------      ----
OpenSSH                    ALLOW       Anywhere
Nginx HTTP                 ALLOW       Anywhere
OpenSSH (v6)               ALLOW       Anywhere (v6)
Nginx HTTP (v6)            ALLOW       Anywhere (v6)

With the new firewall rule added, you can test if the server is up and running by accessing your server’s domain name or public IP address in your web browser.

If you do not have a domain name pointed at your server and you do not know your server’s public IP address, you can find it by running the following command:

This will print out a few IP addresses. You can try each of them in turn in your web browser.

As an alternative, you can check which IP address is accessible, as viewed from other locations on the internet:

Type the address that you receive in your web browser and it will take you to Nginx’s default landing page:

http://server_domain_or_IP

If you see this page, it means you have successfully installed Nginx and enabled HTTP traffic for your web server.

Step 2 — Installing MySQL

Now that you have a web server up and running, you need to install the database system to be able to store and manage data for your site. MySQL is a popular database management system used within PHP environments.

Again, use apt to acquire and install this software:

When prompted, confirm installation by typing Y, and then ENTER.

When the installation is finished, it’s recommended that you run a security script that comes pre-installed with MySQL. This script will remove some insecure default settings and lock down access to your database system. Start the interactive script by running:

This will ask if you want to configure the VALIDATE PASSWORD PLUGIN.

Note: Enabling this feature is something of a judgment call. If enabled, passwords which don’t match the specified criteria will be rejected by MySQL with an error. It is safe to leave validation disabled, but you should always use strong, unique passwords for database credentials.

Answer Y for yes, or anything else to continue without enabling.

VALIDATE PASSWORD PLUGIN can be used to test passwords
and improve security. It checks the strength of password
and allows the users to set only those passwords which are
secure enough. Would you like to setup VALIDATE PASSWORD plugin?

Press y|Y for Yes, any other key for No:

If you answer “yes”, you’ll be asked to select a level of password validation. Keep in mind that if you enter 2 for the strongest level, you will receive errors when attempting to set any password which does not contain numbers, upper and lowercase letters, and special characters, or which is based on common dictionary words.

There are three levels of password validation policy:

LOW    Length >= 8
MEDIUM Length >= 8, numeric, mixed case, and special characters
STRONG Length >= 8, numeric, mixed case, special characters and dictionary              file

Please enter 0 = LOW, 1 = MEDIUM and 2 = STRONG: 1

Regardless of whether you chose to set up the VALIDATE PASSWORD PLUGIN, your server will next ask you to select and confirm a password for the MySQL root user. This is not to be confused with the system root. The database root user is an administrative user with full privileges over the database system. Even though the default authentication method for the MySQL root user dispenses the use of a password, even when one is set, you should define a strong password here as an additional safety measure. We’ll talk about this in a moment.

If you enabled password validation, you’ll be shown the password strength for the root password you just entered and your server will ask if you want to continue with that password. If you are happy with your current password, enter Y for “yes” at the prompt:

Estimated strength of the password: 100 
Do you wish to continue with the password provided?(Press y|Y for Yes, any other key for No) : y

For the rest of the questions, press Y and hit the ENTER key at each prompt. This will remove some anonymous users and the test database, disable remote root logins, and load these new rules so that MySQL immediately respects the changes you have made.

When you’re finished, test if you’re able to log in to the MySQL console by typing:

This will connect to the MySQL server as the administrative database user root, which is inferred by the use of sudo when running this command. You should see output like this:

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 22
Server version: 8.0.19-0ubuntu5 (Ubuntu)

Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> 

To exit the MySQL console, type:

Notice that you didn’t need to provide a password to connect as the root user, even though you have defined one when running the mysql_secure_installation script. That is because the default authentication method for the administrative MySQL user is unix_socket instead of password. Even though this might look like a security concern at first, it makes the database server more secure because the only users allowed to log in as the root MySQL user are the system users with sudo privileges connecting from the console or through an application running with the same privileges. In practical terms, that means you won’t be able to use the administrative database root user to connect from your PHP application. Setting a password for the root MySQL account works as a safeguard, in case the default authentication method is changed from unix_socket to password.

For increased security, it’s best to have dedicated user accounts with less expansive privileges set up for every database, especially if you plan on having multiple databases hosted on your server.

Note: At the time of this writing, the native MySQL PHP library mysqlnd doesn’t support caching_sha2_authentication, the default authentication method for MySQL 8. For that reason, when creating database users for PHP applications on MySQL 8, you’ll need to make sure they’re configured to use mysql_native_password instead. We’ll demonstrate how to do that in Step 6.

Your MySQL server is now installed and secured. Next, we’ll install PHP, the final component in the LEMP stack.

Step 3 – Installing PHP

You have Nginx installed to serve your content and MySQL installed to store and manage your data. Now you can install PHP to process code and generate dynamic content for the web server.

While Apache embeds the PHP interpreter in each request, Nginx requires an external program to handle PHP processing and act as a bridge between the PHP interpreter itself and the web server. This allows for a better overall performance in most PHP-based websites, but it requires additional configuration. You’ll need to install php-fpm, which stands for “PHP fastCGI process manager”, and tell Nginx to pass PHP requests to this software for processing. Additionally, you’ll need php-mysql, a PHP module that allows PHP to communicate with MySQL-based databases. Core PHP packages will automatically be installed as dependencies.

To install the php-fpm and php-mysql packages, run:

When prompted, type Y and ENTER to confirm installation.

You now have your PHP components installed. Next, you’ll configure Nginx to use them.

Step 4 — Configuring Nginx to Use the PHP Processor

When using the Nginx web server, we can create server blocks (similar to virtual hosts in Apache) to encapsulate configuration details and host more than one domain on a single server. In this guide, we’ll use your_domain as an example domain name. To learn more about setting up a domain name with DigitalOcean, see our introduction to DigitalOcean DNS.

On Ubuntu 20.04, Nginx has one server block enabled by default and is configured to serve documents out of a directory at /var/www/html. While this works well for a single site, it can become difficult to manage if you are hosting multiple sites. Instead of modifying /var/www/html, we’ll create a directory structure within /var/www for the your_domain website, leaving /var/www/html in place as the default directory to be served if a client request doesn’t match any other sites.

Create the root web directory for your_domain as follows:

Next, assign ownership of the directory with the $USER environment variable, which will reference your current system user:

Then, open a new configuration file in Nginx’s sites-available directory using your preferred command-line editor. Here, we’ll use nano:

This will create a new blank file. Paste in the following bare-bones configuration:

server {
    listen 80;
    server_name your_domain www.your_domain;
    root /var/www/your_domain;

    index index.html index.htm index.php;

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

    location ~ \.php$ {
        include snippets/fastcgi-php.conf;
        fastcgi_pass unix:/var/run/php/php7.4-fpm.sock;
     }

    location ~ /\.ht {
        deny all;
    }

}

Here’s what each of these directives and location blocks do:

• listen — Defines what port Nginx will listen on. In this case, it will listen on port 80, the default port for HTTP.
• root — Defines the document root where the files served by this website are stored.
• index — Defines in which order Nginx will prioritize index files for this website. It is a common practice to list index.html files with a higher precedence than index.php files to allow for quickly setting up a maintenance landing page in PHP applications. You can adjust these settings to better suit your application needs.
• server_name — Defines which domain names and/or IP addresses this server block should respond for. Point this directive to your server’s domain name or public IP address.
• location / — The first location block includes a try_files directive, which checks for the existence of files or directories matching a URI request. If Nginx cannot find the appropriate resource, it will return a 404 error.
• location ~ \.php$ — This location block handles the actual PHP processing by pointing Nginx to the fastcgi-php.conf configuration file and the php7.4-fpm.sock file, which declares what socket is associated with php-fpm.
• location ~ /\.ht — The last location block deals with .htaccess files, which Nginx does not process. By adding the deny all directive, if any .htaccess files happen to find their way into the document root ,they will not be served to visitors.

When you’re done editing, save and close the file. If you’re using nano, you can do so by typing CTRL+X and then y and ENTER to confirm.

Activate your configuration by linking to the config file from Nginx’s sites-enabled directory:

Then, unlink the default configuration file from the /sites-enabled/ directory:

Note: If you ever need to restore the default configuration, you can do so by recreating the symbolic link, like this:

This will tell Nginx to use the configuration next time it is reloaded. You can test your configuration for syntax errors by typing:

If any errors are reported, go back to your configuration file to review its contents before continuing.

When you are ready, reload Nginx to apply the changes:

Your new website is now active, but the web root /var/www/your_domain is still empty. Create an index.html file in that location so that we can test that your new server block works as expected:

Include the following content in this file:

<html>
  <head>
    <title>your_domain website</title>
  </head>
  <body>
    <h1>Hello World!</h1>

    <p>This is the landing page of <strong>your_domain</strong>.</p>
  </body>
</html>

Now go to your browser and access your server’s domain name or IP address, as listed within the server_name directive in your server block configuration file:

http://server_domain_or_IP

You’ll see a page like this:

If you see this page, it means your Nginx server block is working as expected.

You can leave this file in place as a temporary landing page for your application until you set up an index.php file to replace it. Once you do that, remember to remove or rename the index.html file from your document root, as it would take precedence over an index.php file by default.

Your LEMP stack is now fully configured. In the next step, we’ll create a PHP script to test that Nginx is in fact able to handle .php files within your newly configured website.

Step 5 –Testing PHP with Nginx

Your LEMP stack should now be completely set up. You can test it to validate that Nginx can correctly hand .php files off to your PHP processor.

You can do this by creating a test PHP file in your document root. Open a new file called info.php within your document root in your text editor:

Type or paste the following lines into the new file. This is valid PHP code that will return information about your server:

<?php
phpinfo();

When you are finished, save and close the file by typing CTRL+X and then y and ENTER to confirm.

You can now access this page in your web browser by visiting the domain name or public IP address you’ve set up in your Nginx configuration file, followed by /info.php:

http://server_domain_or_IP/info.php

You will see a web page containing detailed information about your server.

Also read : How to Back Up and Restore a MySQL Database