Heat (software)

Heat (software)
Name	Heat
Developer	OpenStack Foundation
Release date	2012
Programming language	Python
Operating system	Linux
License	Apache License 2.0

Heat (software) is an orchestration component designed to automate the provisioning and management of cloud resources. Created as part of the OpenStack ecosystem, Heat provides a template-driven approach to describe infrastructure and services, enabling repeatable deployments across heterogeneous environments.

Overview

Heat implements orchestration for OpenStack clouds, exposing a RESTful API compatible with AWS CloudFormation concepts and templates. It integrates with multiple OpenStack projects including Nova (OpenStack), Neutron (software), Cinder (OpenStack), Glance (OpenStack), and Keystone (OpenStack), allowing users to coordinate compute, network, block storage, image, and identity services. Heat templates are written in a declarative YAML format and can reference resources such as Heat stacks, Heat templates, OS::Nova::Server, OS::Neutron::Net, and OS::Cinder::Volume types to define complex topologies.

Architecture and Components

Heat's architecture comprises several cooperating services and plugins that interact with OpenStack projects and external systems. Core components include the Heat API service, Heat engine, Heat conductor, and Heat database; these exchange messages via RabbitMQ and persist state in MySQL or MariaDB. The Heat engine translates template resources into actions for drivers such as the Nova compute driver, Neutron network driver, and Cinder volume driver, while the Heat API provides authentication and authorisation through Keystone (OpenStack). Heat also supports a Heat Orchestration Template parser, a template translation layer for AWS CloudFormation compatibility, and resource plugins for extended integrations like Magnum (OpenStack), Sahara (OpenStack), and TripleO.

Workflow and Features

Users create Heat templates that describe stacks, resources, outputs, parameters, and notifications; the Heat engine processes stack lifecycle operations including create, update, suspend, resume, rollback, and delete. Heat supports intrinsic functions such as get_attr, get_param, and join, enabling composition with resources like OS::Heat::ScalingPolicy and OS::Heat::AutoScalingGroup for dynamic scaling tied to Ceilometer or Monasca metrics. Features include resource reconciliation, nested stacks, software configuration via Cloud-Init, deployment-time dependencies, signal handling for asynchronous configuration, and a plugin system for custom resource types. Heat can orchestrate multi-tenant deployments, apply stack-level policies, and integrate with orchestration drivers such as Mistral (OpenStack) for workflow-level automation.

Use Cases and Deployments

Heat is used for reusable infrastructure-as-code scenarios including multi-tier web applications, network function virtualization (NFV) services, continuous delivery pipelines, and platform-as-a-service (PaaS) provisioning. Operators deploy Heat in public clouds built on OpenStack, private clouds in enterprises like finance and telecommunications, and research clouds at institutions partnering with projects such as CERN and NASA. Typical deployments orchestrate resources across compute fleets managed by Nova (OpenStack), virtual networks via Neutron (software), persistent volumes through Cinder (OpenStack), and images stored in Glance (OpenStack), often combined with container platforms like Kubernetes and Docker for hybrid VM/container stacks.

Development and Community

Heat development is coordinated through the OpenStack Foundation governance model with code contributions managed on Gerrit and issue tracking on StoryBoard; releases follow the OpenStack cycle aligning with projects such as Horizon (OpenStack), Keystone (OpenStack), and Ceilometer. The community includes individual contributors and organizations including Red Hat, Canonical (company), IBM and Intel Corporation who maintain resource plugins, CI jobs in Zuul, and design discussions on OpenStack Summit venues. Documentation, template examples, and project roadmaps are maintained in the Heat repository and discussed on OpenStack Mailing Lists and community meetings.

Security and Compliance

Heat relies on the identity and policy controls of Keystone (OpenStack) and supports Role-Based Access Control (RBAC) through policies defined in policy.json files. Secure deployments harden Heat API endpoints with TLS certificates managed by projects like Barbican (OpenStack) and enforce audit trails via integration with Auditd or logging stacks forwarded to Elasticsearch and Kibana. Compliance in regulated environments often references standards and best practices from vendors and auditors such as PCI DSS, ISO/IEC 27001, and SOC 2 frameworks when deploying stacks that handle sensitive workloads. Security features include encrypted parameter support, stack-level resource access scoping, and plugin review processes within the OpenStack governance model.

Category:OpenStack