Creating subdomain on amazon ubuntu Ec2

1. Create a directory from command line

sudo touch /var/www/your-directory

2. Create a conf file on location /etc/apache2/site-available/

 i. sudo touch /etc/apache2/site-available/your-directory-name.domainname.com.conf
 ii. Just copy 000-default.config data to newly created file above
 sudo cp /etc/apache2/site-available/000-default.conf 
/etc/apache2/site-available/your-directory-name.domainname.com.conf
 iii. open file for edit 
 sudo nano /etc/apache2/site-available/your-directory-name.domainname.com.conf
 and replace 
 
 DocumentRoot /var/www/your-directory-name
 
 iv. sudo service apache2 reload.
 v. sudo service apache2 restart. 

3. After above process go to amazon hosted zone just follow below steps

 1. create a records set put name of your choice in name required fields
 2. put www.yourdomain.com. in value and save records set.