OpenStack Heat provides a cloud-native orchestration engine for deploying and managing applications and infrastructure in an OpenStack environment. The Heat API, also known as the Heat REST API or Heat API service, is a component of OpenStack Heat that exposes a RESTful API for interacting with Heat and performing orchestration tasks.
The Heat API enables users to create, update, and delete stacks, which are collections of resources defined in Heat templates. It provides a set of endpoints that allow users to perform various operations, such as creating stacks, listing stacks, updating stacks, retrieving stack details, and executing stack actions.
Here are some key features and functionalities of the Heat API:
- Templates: Heat uses templates written in YAML or JSON format to describe the desired infrastructure and resource configuration. The Heat API allows users to submit these templates to create stacks. Templates define resources like virtual machines, networks, storage volumes, load balancers, and more.
- Stack Operations: The Heat API enables users to create stacks based on templates, update existing stacks by modifying the template or resource properties, and delete stacks to release the allocated resources. It also supports listing stacks, retrieving stack details, and querying stack events and resources.
- Resource Management: The Heat API provides methods to manage resources within a stack. Users can retrieve information about resources, update resource properties, and perform operations like suspend, resume, and delete on individual resources.
- Stack Actions: Heat supports various stack actions, such as stack suspension, resumption, and rollback. These actions allow users to pause a stack’s activity, resume its execution, or revert to a previous known state in case of failures.
- Stack Events and Notifications: Heat generates events and notifications during the lifecycle of a stack. The Heat API allows users to query and retrieve these events, providing insights into the progress and status of stack operations.
- Authentication and Access Control: The Heat API integrates with the OpenStack Identity service (Keystone) to authenticate and authorize API requests. It enforces access controls based on user roles and permissions, ensuring secure access to orchestration functionality.
- Integration with Other OpenStack Services: Heat integrates with other OpenStack services like Nova (compute), Neutron (networking), Cinder (block storage), Glance (image), and more. This integration allows Heat to provision and manage resources across multiple services as part of a stack.
It’s important to note that the Heat API is just one component of the Heat service. Heat also includes other components like the Heat Engine, which performs the orchestration tasks, and the Heat Clients, which provide command-line and SDK interfaces for interacting with Heat.
Overall, the Heat API provides a powerful interface for managing the deployment and lifecycle of infrastructure resources in an OpenStack environment. It enables users to automate and streamline the process of provisioning and managing complex application stacks and infrastructure configurations.