# Introduction The [Cloud Provider Ranker](https://github.com/indigo-dc/CloudProviderRanker) is a standalone REST WEB Service which ranks cloud provider services using rules implemented with the [Drools framework](https://drools.org). The [INDIGO PaaS Orchestrator](https://github.com/indigo-dc/orchestrator) interacts with this service in order to obtain the rank of two or more cloud services depending on the match with specific rules. The aim of this micro component is to fully decouple the ranking logic from the Orchestrator's business logic. The Cloud Provider Ranker can be installed on any machine which is reachable from the Orchestrator via TCP connection (including the machine running the Orchestrator itself). It is a fully stateless service; it can be used by several Orchestrators, or by any other REST client complying with the expected JSON request. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://indigo-dc.gitbook.io/cloud-provider-ranker/master.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.