How To Install the Apache Web Server on Ubuntu

Introduction
The Apache HTTP server is the most widely-used web server in the world. It provides many powerful features including dynamically loadable modules, robust media support, and extensive integration with other popular software.

In this guide, we’ll discuss how to install an Apache web server on your Ubuntu 16.04 server.

Prerequisites
Before you begin this guide, you should have a regular, non-root user with sudo privileges configured on your server. Additionally, you will need to configure a basic firewall to block non-essential ports. You can learn how to configure a regular user account and set up a firewall for your server by following our initial server setup guide for Ubuntu 16.04.

When you have an account available, log in as your non-root user to begin.

 

Step 1: Install Apache

Apache is available within Ubuntu’s default software repositories, so we will install it using conventional package management tools.

We will begin by updating the local package index to reflect the latest upstream changes. Afterwards, we can install the apache2 package:

sudo apt-get update
sudo apt-get install apache2

After confirming the installation, apt-get will install Apache and all required dependencies.

 

Step 2: Check your Web Server

At the end of the installation process, Ubuntu 16.04 starts Apache. The web server should already be up and running.

We can check with the systemd init system to make sure the service is running by typing:

sudo systemctl status apache2

or:

sudo service apache2 status

 

Step 3: Get Familiar with Important Apache Files and Directories

Now that you 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 Apache page you saw earlier, is served out of the /var/www/html directory. This can be changed by altering Apache configuration files.
Server Configuration
/etc/apache2: The Apache configuration directory. All of the Apache configuration files reside here.
/etc/apache2/apache2.conf: The main Apache configuration file. This can be modified to make changes to the Apache global configuration. This file is responsible for loading many of the other files in the configuration directory.
/etc/apache2/ports.conf: This file specifies the ports that Apache will listen on. By default, Apache listens on port 80 and additionally listens on port 443 when a module providing SSL capabilities is enabled.
/etc/apache2/sites-available/: The directory where per-site “Virtual Hosts” can be stored. Apache 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 with the a2ensite command.
/etc/apache2/sites-enabled/: The directory where enabled per-site “Virtual Hosts” are stored. Typically, these are created by linking to configuration files found in the sites-available directory with the a2ensite. Apache reads the configuration files and links found in this directory when it starts or reloads to compile a complete configuration.
/etc/apache2/conf-available/, /etc/apache2/conf-enabled/: These directories have the same relationship as the sites-available and sites-enabled directories, but are used to store configuration fragments that do not belong in a Virtual Host. Files in the conf-available directory can be enabled with the a2enconf command and disabled with the a2disconf command.
/etc/apache2/mods-available/, /etc/apache2/mods-enabled/: These directories contain the available and enabled modules, respectively. Files in ending in .load contain fragments to load specific modules, while files ending in .conf contain the configuration for those modules. Modules can be enabled and disabled using the a2enmod and a2dismod command.
Server Logs
/var/log/apache2/access.log: By default, every request to your web server is recorded in this log file unless Apache is configured to do otherwise.
/var/log/apache2/error.log: By default, all errors are recorded in this file. The LogLevel directive in the Apache configuration specifies how much detail the error logs will contain.
Conclusion
Now that you have your web server installed, you have many options for the type of content to serve and the technologies you want to use to create a richer experience.

Learn how to use Apache Virtual Hosts here. If you’d like to build out a more complete application stack, check out this article on how to configure a LAMP stack on Ubuntu 16.04.
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