The objective of the "cloud index" is to monitor the cloud level of an IT system in order to monitor and to communicate in a simple way to the level of cloud reached.
Here's the definition I use.
The IT system is defined as a sum of Business Services (i.e. applications, see ITIL definition).
Each business service is characterized by a "feature_size".
The "feature_size" express the complexity of the application (kind of "function point" approach).
For each business service, we express it's "cloud_level" on a scale from 0 to 100 :
* **0**** ** : the business service is hosted on dedicated servers on premise * **10** : the business service is hosted on shared servers (via virtualization for example) on servers on premise. * **20** : the business service is hosted on an external datacenter * **50** : the business service is hosted on a IaaS platform * **60** : the business service is on a PaaS platform * **100** : the business service is supported by a full Saas Solution.
Based on this, the cloud index is defined as the weighted average of the business services "cloud_level" weighted by the "feature_size".