It takes the deployment requests, expressed through templates written in TOSCA YAML Simple Profile v1.0, and deploys them on the best cloud site available. In order to do that 1. it gathers SLAs, monitoring info and other data from other platform services, 2. it asks to the cloud provider ranker for a list of the best cloud sites.
The PaaS Orchestrator needs the presence of the following INDIGO services:
SLAM (SLA Manager): allows to retrieve all the SLAs of the user
CMDB (Configuration Manager DataBase): contains all the cloud sites information, like the identity endpoint, the OCCI endpoint, etc...
Zabbix Wrapper (REST wrapper for Zabbix): allows to retrieve monitoring metrics to zabbix through a REST interface
CPR (Cloud Provider Ranker): it receives all the information retrieved from the aforementioned services and provides the ordered list of the best sites