To use the Customer Management Service effectively, you should understand several key concepts.
A customer is an individual or a business entity that purchases products or services, or both from Rackspace. Each customer is uniquely identified by a number called Rackspace Customer Number (RCN).
A customer account represents part of a customer's portfolio across Rackspace. This part of the portfolio can have product, contact, billing, identity, and support configured for it. Conceptually, customer accounts are independently managed. For example, a customer can have multiple products associated with multiple accounts, such as a dedicated server associated with a managed account and cloud servers, or cloud files associated with a cloud account. The only link between the managed and cloud accounts is that they belong to the same customer.
A contact is a person who is associated with a customer account. Each contact is uniquely identified by a number called Rackspace Person Number(RPN).
Metadata are entity-specific data that can be stored for a customer account. Metadata contains two fields: key and value.
The key is made up of two colon-delimited (:) elements: namespace and key.
The value is a simple string value for the content management system (CMS) to store for a particular element.
Metadata elements are open, read, and write restricted.