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Apache Web Server Setup Guide

19 Jan 2023

Individual portion of Module 2 from CSE 330/503S: “Rapid Prototype Development and Creative Programming” at Washington University in St. Louis. The Apache web server will be installed and configured on an AWS EC2 instance. A Mac laptop is used as the local machine.

Table of Contents

Create an AWS EC2 Instance

Log in to your AWS Management Console and launch a new instance. Choose the image labeled “Amazon Linux 2 AMI” and make sure you have \(64\)-bit x86 selected. Make sure your security group includes a rule of type SSH, protocol TCP, port range 22, and source of 0.0.0.0/0 or Anywhere.

In the dialog box, create a new key pair, enter some name for it (e.g., sp2023), and then click “Create & Download Your Key Pair”. A .pem file will be downloaded. This is the private key for the default user (ec2-user on AMI). Save your key somewhere secure. Click “Launch Instances” and you are ready to launch your virtual server.

SSH Configuration

Open a terminal window on your local computer (in my case a MacBook Air) and run the following command:

# Passphrase is optional
ssh-keygen

Your keys should have created in the directory ~/.ssh:

$ ls ~/.ssh
id_rsa  id_rsa.pub

The first file stores your private key and the second stores the corresponding public key. If you are using macOS like me, run the following command to add your key to the SSH agent:

ssh-add

Then, you need to do the following to fix the permissions:

chgrp Users ~/.ssh/id_rsa

chmod 600 ~/.ssh/id_rsa

Log in as the default user

To connect to the default user on your Amazon EC2 instance, run this command in your local terminal:

ssh -i </path/to/default-privatekey.pem> <ec2-user>@<ec2-xx-xx-xx-xx.compute-1.amazonaws.com>

Then you need to correctly set the permissions on your .pem file:

chmod 600 </path/to/default-privatekey.pem>

Create a new user with SSH permissions

On your EC2 instance, run the following commands:

$ sudo useradd -r -m -c "<your full name>" <username>
$ sudo passwd <username>
Enter new UNIX password: 
Retype new UNIX password:

For security reasons, you should never SSH into your server as the root user. Instead, you should use a normal user to whom you give sudo privileges. To give a user sudo privileges, use the command visudo, which opens up the sudo configuration file in the system’s default text editor. (Never edit the file /etc/sudoers directly!) sudo users are specified using lines similar to:

<username>  ALL=(ALL)   ALL

Add that line immediately below the line defining root:

root    ALL=(ALL)   ALL

When you are finished, save and close the file. Finally, restart the SSH server:

sudo service ssh restart || sudo service sshd restart

Okay, cool: you have created your custom username on your remote instance. Now, you need to enable this account to accept your SSH key when authenticating. To do this, you need to add your public key to a file named authorized_keys, which is stored in your remote username’s SSH configuration directory. To create the directory and edit the file, run on your instance:

# Switch to your own user to ensure that permissions are set correctly:
su <username>

# Change the working directory to your user's home directory
cd

# Make the nonexistent SSH configuration directory and set its permissions:
mkdir .ssh
chmod 700 .ssh

# Create authorized_key file and set its permissions:
touch .ssh/authorized_keys
chmod 600 .ssh/authorized_keys

Inside of the authorized_keys file, paste in your public key. Your public key is the content of ~/.ssh/id_rsa.pub on your local machine. If you are using Mac OS X, run:

cat ~/.ssh/id_rsa.pub | pbcopy

At this stage, you can log in as your new user:

ssh <username>@<ec2-xx-xx-xx-xx.compute-1.amazonaws.com>

To save from typing this command in every time you want to access your server, you can set an alias in your terminal, e.g.:

alias aws='ssh <username>@<ec2-xx-xx-xx-xx.compute-1.amazonaws.com>'

Set Up the Apache Web Server

Install essential packages

The package management tool in Red Hat Enterprise Linux (RHEL), and therefore also your Amazon EC2 instance, is rpm. If you have an rpm package, you can install it by:

rpm -i <somepackage>.rpm

This requires that <somepackage>.rpm be in your current directory, which means you will have to download the file yourself (or create it). It requires you to manually install any dependencies the package has. A better alternative is to use a repository-based package manager. In RHEL, this is yum. Before you install new software, you need to ensure that your local list of available packages is up-to-date. Run the following commands to perform this operation:

yum check-update

After you have ensured that your package list is synced with the remote repository, you can start installing packages. To install a package, issue the following command:

yum install <somepackage>

To save you some headaches later on, it is recommended that you install a few essential package bundles when you first create a new Linux instance. These packages include things like Make and a C compiler.

sudo yum groupinstall "Development Tools"

sudo yum install kernel-devel kernel-headers

Set the time zone

The time zone files are in the directory /usr/share/zoneinfo. They are further organized within subdirectories grouped by region. For instance, Rome’s time zone file is stored within /usr/share/zoneinfo/Europe. In order to set the time zone, simply copy the desired time zone file to our /etc directory as a new file named localtime. For example, to set the the machine’s system time to Rome’s time zone, we would enter the command:

sudo cp /usr/share/zoneinfo/Europe/Rome /etc/localtime

Install the Apache web server

In yum, Apache is distributed under the package name httpd (for “hypertext transfer protocol daemon”):

sudo yum update

sudo yum install httpd

You’ll need to run this command to add Apache as a startup item:

sudo /sbin/chkconfig --levels 235 httpd on

In RHEL, most Apache configurations are stored in /etc/httpd/conf/httpd.conf and others are located in the directory /etc/httpd/conf.d/. At this point, Apache has been installed, but is not yet running. To start the web server, run this command:

sudo /usr/sbin/apachectl start

In order for your web server to be accessible, you need to open up Port 80 on your EC2 instance. (By default amazon blocks all traffic to our instance.) Go to the “Security Groups” under “Network & Security” on the AWS EC2 website. Select your security group and add a new Custom TCP rule with a port range of 80. Leave the source at 0.0.0.0/0 (for all traffic). Click “Add Rule”, and then click “Apply Rule Change”.

To make sure things are working, create a file, like hello.txt, in your web server root. Give it some content (might I suggest “Hello, world!”). The web server root is at /var/www/html. You should now be able to visit your server load up the file using your web browser! Example Link: http://ec2-xxx-xxx-xxx-xx.compute-1.amazonaws.com/hello.txt. Depending on the city in which your server is located, your link might look like: http://ec2-xxx-xxx-xxx-xxx.us-west-2.compute.amazonaws.com/hello.txt.

Finally, you need to edit the master Apache configuration file. Open /etc/httpd/conf.d/userdir.conf in your favorite text editor and find the line that says:

UserDir disabled

Change it to:

UserDir disabled root

Additionally, find the line that says:

#UserDir public_html

and uncomment it. This tells Apache that the directory containing each user’s html files is a subdirectory of their home directory called public_html. You may also need to change the permissions of your user directory and your public_html directory to allow Apache to read and execute inside them. To do this, run the following commands:

mkdir /home/<username>/public_html

sudo chmod o+x /home/<username>

sudo chmod o+rx /home/<username>/public_html

Restart Apache. There are several different ways to restart Apache; they all functionally do (almost) the same thing, so choose your favorite:

sudo /usr/sbin/apachectl restart
sudo apachectl restart  # if /usr/sbin is in your PATH (which it is *not* by default in RHEL)
sudo /etc/init.d/httpd restart
sudo /sbin/service httpd restart
sudo service httpd restart

PHP Installation and Workspace Setup

PHP is a server-side scripting language widely used in web development. PHP is what turns your website from a static file server into a dynamic web application. By default, Apache only knows how to serve static HTML pages to the client. You can write as many HTML pages as you want, which is fine for basic websites. But if you want to have users post to a forum, or process credit card transactions, or make your own online calendar, a server-side language like PHP is what you need. Here are some points to keep in mind:

To install PHP 7.2, run the following command to install php7.2 from the Amazon Linux Extras repository:

sudo amazon-linux-extras install -y php7.2
sudo service php-fpm start

Note that a later version of PHP might not be compatible with the underlying Amazon Linux distribution. Once you install the required packages, restart Apache for the changes to take effect. The PHP configuration file is called php.ini. In RHEL, it is located at /etc/php.ini. Open php.ini in your favorite text editor, find the display_errors option, and set it to On:

display_errors = On

You will need to restart Apache for any php.ini changes to take effect.

The PHP Extension and Application Repository (PEAR) is a package manager that enables you to install classes and/or extensions to PHP. It is available through both the yum and apt repositories under the package name php-pear:

# In RHEL
sudo yum install php-pear

Using PEAR to install PHP extensions is just as easy as yum, apt, gem, and pip. Just run sudo pear install xxx.

If you are using an external SFTP client, you can use FileZilla. Download and install FileZilla from https://filezilla-project.org/download.php?type=client. When you launch FileZilla, go to Edit->Settings or FileZilla->Preferences, and go to the SFTP options (under Connection). Click “Add key file…”. Choose your id_rsa file. (macOS Tip: Press Shift+Command+Period to reveal hidden files in the file chooser window.) On FileZilla’s main screen, there are four fields: Host, Username, Password, and Port. Fill them in as follws:

Then click “Quickconnect”. If everything is configured correctly, FileZilla should log into your server. On the left and right of the FileZilla window, you can drag files between your local computer and your server. Thus, you can edit a file in a text editor on your decktop, and then upload it to your server by simply dragging it from the left pane to the right pane in FileZilla.

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