Describe the concept of patterns as description for cloud services:
Patterns (aka service templates) describe how cloud services and applications are deployed, managed and scaled by an engine supporting the format (domain specific language) of the cloud service.
Patterns describe the structure and topology of a cloud service, i.e. the infrastructure and application components, resources and relationships and related management processes required to deliver the cloud service.
Pattern components are for instance definition of network and storage elements, image, software binaries, install scripts and recipes.
Patterns can either be described in a declarative (e.g. expressed by relationships) or imperative manner (e.g. express by a management plan).
Patterns can be composed out of other templates, e.g. an application pattern may use an infrastructure pattern.