The Orchestration module provides a template-based orchestration for describing a cloud application, by running OpenStack API calls to generate running cloud applications. The software integrates other core components of OpenStack into a one-file template system. The templates allow you to create most OpenStack resource types, such as instances, floating IPs, volumes, security groups and users. It also provides advanced functionality, such as instance high availability, instance auto-scaling, and nested stacks. This enables OpenStack core projects to receive a larger user base. The service enables deployers to integrate with the Orchestration module directly or through custom plug-ins. The Orchestration module consists of the following components: heat command-line client A CLI that communicates with the heat-api to run AWS CloudFormation APIs. End developers can directly use the Orchestration REST API. heat-api componentAn OpenStack-native REST API that processes API requests by sending them to the heat-engine over Remote Procedure Call (RPC). heat-api-cfn component An AWS Query API that is compatible with AWS CloudFormation. It processes API requests by sending them to the heat-engine over RPC. heat-engine Orchestrates the launching of templates and provides events back to the API consumer.