A framework for the orchestration and provision of cloud services based on TOSCA and BPMN

Cloud computing is a consolidated and high-maturity level paradigm which is capable of handling powerful computing environments and providing complex services in a flexible and scalable way. In order to compete in the cloud service market, one of the challenges Cloud providers are faced with is to efficiently automate the service “provisioning” activities through the use of Cloud orchestration techniques. The focus of this paper is the orchestration process. Starting with TOSCA, a well-known standard specification used to represent the complete structure of a Cloud service, we developed an orchestrator capable of automating the workflow of all the tasks required to build up such a service. What makes our approach novel is the definition of a converter component which takes as input a TOSCA service template and transforms it into a BPMN process model that is ready to be fed to a workflow engine. The BPMN notation is used to represent both the workflow and the data associated with each workflow step. To prove the viability of the YAML-to-BPMN conversion process, a software prototype of the system was developed and tested with a sample use case which is discussed in the paper.