Installing the Apache Web Server
Introduction
Apache is an HTTP server, otherwise called web server software. Other HTTP server software exists. Another big one is nginx. An HTTP server essentially makes files on a computer available to others who are able to establish a connection to the computer and view the files with a web browser.
It's important to understand the basics of an HTTP server, and therefore I ask you to read Apache's Getting Started page before proceeding with the rest of this section. Each of the main sections on that page describe the important elements that make up and serve a website, including
- clients, servers, and URLs
- hostnames and DNS
- configuration files and directives
- web site content
- log files and troubleshooting
Installation
Before we install Apache, we need to update our systems first.
sudo apt update
sudo apt -y upgrade
Once the machine is updated,
we can install Apache2 using apt.
First we'll use apt search to identify
the specific package name.
I already know that a lot of results
will be returned,
so let's pipe the apt search command
through head to look at the initial results:
sudo apt search apache2 | head
The package that we're interested in
happens to be named apache2 on Ubuntu.
This is not a given.
On other distributions,
like Fedora,
the Apache package is called httpd.
To learn more about the apache2 package,
let's examine it with the apt show command:
apt show apache2
Once we've confirmed that apache2 is the package
that we want,
we install it with the apt install command.
Press Y to agree to continue after running
the command below:
sudo apt install apache2
Basic checks
One of the things that makes Apache2, and some other web servers, powerful is the library of modules that extend Apache's functionality. We'll come back to modules soon. For now, we're going to make sure the server is up and running, configure some basic things, and then create a basic web site.
To start,
let's use systemctl to acquire some info about apache2 and
make sure it is enabled and running:
systemctl list-unit-files apache2.service
systemctl status apache2
The output shows that apache2 is enabled, which means that it will start running automatically if the computer gets rebooted.
The output of the second command also shows that apache2 is enabled and that it is also active (running).
Creating a web page
Since apache2 is up and running, let's look at the default web page.
There are two ways we can look at the default web page.
We can use a command line web browser.
There are a number available, but
I like w3m.
We can also use our regular web browsers and view the site by entering the IP address of the server in our browser URL bar.
To check with w3m,
we have to install it first:
sudo apt install w3m
Once it's installed, we can visit our default site using the loopback IP address (aka, localhost). From the command line on our server, we can run either of these two commands:
w3m 127.0.0.1
w3m localhost
We can also get the subnet/private IP address
using the ip a command, and
then use that with w3m.
For example, if ip a showed that my NIC
has an IP address of 10.0.1.1, then
I could use w3m with that IP address:
w3m 10.0.1.1
If the apache2 installed and started correctly, then you should see the following text at the top of the screen:
Apache2 Ubuntu Default Page
It works!
To exit w3m,
press q and then y to confirm exit.
To view the default web page using a regular web browser, like Firefox, Chrome, Safari, Edge, or etc., you need to get our server's public IP address. To do that, log into the Google Cloud Console, in the left hand navigation panel, hover your cursor over the Compute Engine link, and then click on VM instances. You should see your External IP address in the table on that page. You can copy that external IP address or simply click on it to open it in a new browser tab. Then you should see the graphical version of the Apache2 Ubuntu Default Page.
Please take a moment to read through the text on the default page. It provides important information about where Ubuntu stores configuration files and what those files do, and document roots, which is where website files go.
Create a Web Page
Let's create our first web page. The default page described above provides the location of the document root at /var/www/html. When we navigate to that location, we'll see that there is already an index.html file located in that directory. This is the Apache2 Ubuntu Default Page that we described above. Let's rename that index.html file, and create a new one:
cd /var/www/html/
sudo mv index.html index.html.original
sudo nano index.html
If you know HTML, then
feel free to write some basic HTML code to get started.
Otherwise, you can re-type the content below
in nano, and
then save and exit out.
<html>
<head>
<title>My first web page using Apache2</title>
</head>
<body>
<h1>Welcome</h1>
<p>Welcome to my web site. I created this site using the Apache2 HTTP server.</p>
</body>
</html>
If you have our site open in your web browser, reload the page, and you should see the new text.
You can still view the original default page by specifying its name in the URL. For example, if your external IP address is 55.222.55.222, then you'd specify it like so:
http://55.222.55.222/index.html.original
User Directories
You may have visited sites in the past that have a tilde in the URL and look like this:
http://example.com/~user/
These are called user directories, and the provide additional path to the document root that's located in users' home directories in a directory called public_html. This is the default document root for user directories, but the default can be changed to different locations. Please read the documentation on what's called the Apache Module mod_userdir before proceeding.
By default, users with accounts on the server need to have a public_html directory in their home directories, and Apache2 needs to be configured to serve sites from those directories. For example, for the user linus, they should have the following file path available:
/home/linus/public_html/
Enable mod_userdir
The configuration file for mod_userdir is
located in /etc/apache2/mods-available/
and is named userdir.conf.
Files in this directory are modules that
are available to Apache2 but that are not
enabled (i.e., they're turned off) by default.
We can view that the userdir.conf file
with the less command:
less /etc/apache2/mods-available/userdir.conf
The default configuration does not need to be modified.
Therefore, all we need to do is enable this module.
To do that, we use the a2enmod Apache2 command
(see man a2enmod for details.)
sudo a2enmod userdir
After enabling, we need to reload the HTTP service, and we can also check its status:
sudo systemctl restart apache2
systemctl status apache2
Create a User Directory Website
Let's say I am logged in as the user linus on the system and
will use that to test if the user directory is working.
First, let's go home.
For me, as the user linus,
that would /home/linus/, and
I just have to type in the cd command and press Enter:
cd
Now I need to create a public_html directory in my home directory (make sure you're in your home directory!), and change into that directory:
mkdir public_html
cd public_html
By default, Apache2 looks for a file named index.html in the document root. I'll create that and add some basic HTML to it:
nano index.html
And in that file:
<html>
<head>
<title>My home site</title>
</head>
<body>
<p>This is my home site.</p>
</body>
</html>
Now simply add /~linus/ to your external IP address in your browser's URL bar. Like so (of course, replace the external IP address with your external IP address and the username with the username that you're using):
http://55.222.55.222/~linus/
Note that this process is pretty easy but that it will be different on other distributions. For example, the Fedora distribution has different Apache2 defaults. Also, on some distributions, we might need to change the directory permissions before this will work. By default, Ubuntu sets directory permissions to on our home directories to:
drwxr-xr-x
That means that any user can view the contents
of our home directories.
And Ubuntu sets directories created with mkdir
in the home directory with these permissions by default:
drwxrwxr-x
These default settings make those directories
world readable, but
other distributions do not default to those permissions.
If the last r-x was set to ---, then
we would need to use the chmod command
to make these directories executable and readable
before files in our public_html directory
could be accessed in a browser.
Conclusion
In this section,
we learned about the Apache2 HTTP server.
We learned how to install it on Ubuntu,
how to use systemd (systemctl) commands
to check its default status,
how to create a basic web page in /var/www/html,
how to view that web page using the w3m
command line browser and with our regular graphical browser,
how to enable the user directory module, and
repeat the steps above to create a website
in our home directories.
In the next section, we will learn how to make our sites applications by installing PHP and enabling the relevant PHP modules.