Introduction to Virtual Host
A virtual host, in its initial days, started with the purpose of hosting more than the website (for e.g. website1.example.com, website2.example.com, etc.) on a single machine. That would also mean to share single machine resources such as memory and CPU. The resources are shared and utilized in such a manner so that maximum efficiency is achieved.
Now with the invention of cloud computing, virtual now serves more purposes than ever such as solutions like virtual application hosting, virtual server hosting, virtual storage hosting and sometimes also virtual/entire data center hosting.
Working of a Virtual Host
There are many ways to configure a virtual host and most of the ways that are used today are given below:
- IP Based
- Port-Based
- Name Based
1. IP Based
It is one of the simplest methods among three and it can be used to apply different directives based on the IP address. In IP based virtual hosting, we use different IPs for each domain.
The multiple IPs will actually point to the unique domains on the server and there would only be one IP for a server. This virtual hosting is achieved by creating multiple IP addresses for the single server.
2. Port-Based
Port-based virtual hosting is also similar to the IP based virtual hosting, the difference is – Instead of using the different IP address for each of the virtual hosts, we use different ports in which the servers are configured to respond to multiple websites that are dependent on the port of the server.
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3. Name Based
Name-based virtual hosts are the most commonly and frequently used virtual hosting technique that is used today. The name-based Virtual host will use the single IP address for all the domains on the given server. When the browser is trying to connect to the server, it will send a message to the server informing about the domain name to which it is trying to connect. When the domain name is provided, the server checks the host configuration and thereby returns the request with the correct website.
How to Create a Virtual Host/ Examples and Illustration?
For the purpose of our illustration, we will be using Apache server to set up the Apache hosts over the Ubuntu Operating System. One reason for selecting Apache is because it is one of the most trusted and reliable servers that is being used to set up Iy.
Prerequisites
You should have an Ubuntu OS with you and an Apache installation.
If Apache is not installed, please install it with the help of following commands:
sudo apt-get update
sudo apt-get install apache2
As for our tutorial, we will be creating the virtual host for domains:
- Test1.com
- Test2.com
Step 1: Create a Directory Structure
The first step is to create a directory structure which will be used to store the site data that we will be serving to site visitors or we will be accepting data from visitors.
So we are going to make directories structure as follows under our document root ( /var/www directory)
sudo mkdir -p /var/www/test1.com/public_html
sudo mkdir -p /var/www/test2.com/public_html
Step 2: Permissions
As we have seen that the directory structure that we have created are owned by the root user. So if you want to change it in order to modify the files in the web directories, we can do it by following:
sudo chown -R $USER:$YOUR_USER_NAME /var/www/test1.com /public_html
sudo chown -R $USER:$ YOUR_USER_NAME /var/www/test2.com /public_html
Step 3: Create Sample (Demo) Pages for Each of the Virtual Hosts
Let us first create the sample/test page for test1.com.
Open it with a vi editor or any editor of your choice and do some HTML things!
vi /var/www/test1.com/public_html/index.html
Once it is open, please write some basic HTML code, save the editor and close it.
<html>
<head>
<title>Home Page of Test1.com<title>
</head>
<body>
<h1>Success! The test1 virtual host is working!</h1>
</body>
</html>
Similarly, we can create the HTML page for the other website i.e. test.com
vi /var/www/test2.com/public_html/index.html
Once it is open, please write some basic HTML code, save the editor and close it.
<html>
<head>
<title>Home Page of Test2.com<title>
</head>
<body>
<h1>Success! The test2 virtual host is working!</h1>
</body>
</html>
Step 4: To \Ccreate the New Files for Virtual Host
These are the files that are having the actual configuration of our hosts. As we have already installed Apache, it comes with a default virtual host file which is known as 000-default.conf and we will be making use of it.
Let us first copy that apache conf file to our first domain:
sudo cp /etc/apache2/sites-available/000-default.conf /etc/apache2/sitesavailable/test1.conf
When this is done, please open it with your favorite editor.
It should look something like below:
<VirtualHost *:80>
ServerAdmin webmaster@localhost
DocumentRoot /var/www/html
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>
Here we need to change the email to replace it with the email of the server admin.
ServerAdmin admin@test1.com
Now the next thing is to add 2 directives which are ServerName (This should be your domain) and ServerAlias. It is achieved as:
ServerName test1.com
ServerAlias www.test2.com
Finally, please change the location of the document root of our domain.
It can be achieved through:
DocumentRoot /var/www/test1.com/public_html.
Similarly, please follow the above procedures for our second domain as well.
Step 5: To Enable Files of Virtual Host
We have newly set up our virtual files and now we need to enable them.
This can be done via below command:
sudo a2ensite test1.com.conf
sudo a2ensite test2.com.conf
Once it is done, please restart our apache server:
sudo service apache2 restart
Step 6: Test your Results
Now it is time to test your results.
Open up a web browser and fire up the domain name of your websites one by one and you should see pages like below:
Conclusion
In this article, we started with the basics of virtual host and then we saw different ways through which hosts are configured.
Finally, we also had a practical demo of how we can set up it using Apache as our web server and Linux as our OS.
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