If you have an application that requires multiple, or a dynamic range of subdomains, one solution can be to create a wildcard subdomain entry. This can be done within cPanel.
1. Within cPanel, go to Subdomains, and create an entry with an asterisk (*), such as *.mydomain.com.
2. Verify that a wildcard, * A record has been created, by viewing the entries via Advanced DNS Editor.
3. The software you install in the hosting space will need to handle and support wildcard DNS logic. A sniffer script, such as one that actively parses the complete hostname, and then determines the subdomain being requested.
An example of a wildcard subdomain application would be a WordPress multisite installation.