As a distinct and remotely accessible environment, a cloud represents an option for the deployment of IT resources. An IT resource that is hosted in a conventional IT enterprise within an organizational boundary (that does not specifi cally represent a cloud) is considered to be located on the premises of the IT enterprise, or on-premise for short. In other words, the term "on-premise" is another way of stating "on the premises of a controlled IT environment that is not cloud-based." This term is used to qualify an IT resource as an alternative to "cloud-based." An IT resource that is on-premise cannot be cloud-based, and vice-versa.
Note the following key points:
- An on-premise IT resource can access and interact with a cloud-based IT resource.
- An on-premise IT resource can be moved to a cloud, thereby changing it to a cloud-based IT resource.
- Redundant deployments of an IT resource can exist in both on-premise and cloudbased environments.
If the distinction between on-premise and cloud-based IT resources is confusing in relation to private clouds (described in the Cloud Deployment Models section of Chapter 4), then an alternative qualifi er can be used.