What is a role?

A role categorizes an instance. It defines the scope of what the instance is supposed to do within its cloud. Our standard roles include things like a MySQL master, a web server and a Rails application server. You can assign multiple roles to one instance, although we recommend keeping the number of roles small.

If you need to you're free to add as many as you like, as their a neat way of giving an instance a specific context. If you have several of those, who are we to judge? After all, when you add custom Chef cookbooks to your cloud it can make sense to have several distinct roles spread across different instances in your cloud.

Here's an example of an instance that serves as both a Redis server and Rails application server: