OPS335 Lab 5

In this lab we will have a quick look at several separate technologies that are often used together with the Apache web server to install and run web applications.

Apache on its own does little more than serve text pages, images, and other static files. You can format those pages to look nice but they won't have any dynamic functionality - they will always look the same.

To add life to a website more than just the web server is needed. A popular acronym is LAMP. It stands for Linux, Apache, MySQL, and PHP (or Python). This week we will set up this stack to give us a website that does webmail (send and receive email in a web browser).

LAMP

Linux

We'll need a new virtual machine. Because you probably forgot how to install one - go through the exercise again, and set up a vm4 from scratch. Only a minimal setup is needed. Configure it in the same way that you've configured the other three main VMs. This should be a quick exercise for you by now, including:

• The installation,
• Connecting to the correct network with a static IP (the address 192.168.X.5 should be available),
• Making sure you're using your internal DNS server,
• Configuring default rules for your iptables firewall,
• Allowing passwordless login from the host's root account,
• Disabling selinux since you don't know how to configure it properly.

As an interesting exercise: configure all your network settings (except the firewall) during the installation wizard.

Apache

Install Apache (the package name is httpd), start the service, make it start automatically, and allow access to it through the firewall (Apache serves HTTP traffic which goes over TCP port 80).

Now if you navigate to vm4.youruserid.org in a web browser in your host - you should see an Apache testing page.

Delete the file /etc/httpd/conf.d/welcome.conf to get rid of the default page.

We're not going to have a lot of time to study various Apache options so we'll tell you what you're looking for but you have to find it yourself.

DocumentRoot specifies where Apache will look for documents to serve.

Now create the file index.html in your DocumentRoot directory with the following contents (replace the date with the current one):

Hello, this is a web page on vm4.yourid.org and the current time is Mar 28 22:16:27 EDT 2016!

If you refresh the page in Firefox - you should see the contents of your index.html. If you like - you can specify the filename index.html in the address but there's no need since it's a default.

It may seem obvious - but notice that the time doesn't change as you refresh the page.

PHP

We'll replace our index.html file with an index.php with the following contents:

Hello, this is a web page on vm4.yourid.org and the current time is <?php system("date"); ?>!

Notice that in a web browser the index.php file isn't treated as a default page and the contents don't contain the date, but instead have exactly the text above. That's because the PHP interpreter isn't installed by default on CentOS. Install it. The package comes with a working default Apache configuration so you don't need to enable it manually.

Refresh the page, notice that you now see the date instead of the call to the date command. This is a trivial example of dynamic web content - it doesn't need to be the same every time you look at it.

MySQL

MySQL is used to allow storage and retrieval of structured data. SQL is used by countless services for all kinds of use cases. Again we won't spend much time learning the details of MySQL configuration but you need a basic server set up. You may remember setting up MySQL from OPS235 - we're doing the nearly identical thing here.

Install MySQL. You may notice that it's actually called MariaDB now. They are two separate projects run by different groups but they are compatible so you can use documentation from one to configure the other. Make sure you have not just the client but also the server software.

When you start the service - you'll get some instructions in the log file about setting a root password. Even though we won't configure our service to be accessible over the network - you should get into the habit of doing this with every MySQL installation you ever make.