OpenStack Heat

OpenStack Heat
Name	OpenStack Heat
Developer	OpenStack Foundation
Initial release	2012
Written in	Python (programming language)
Operating system	Linux
License	Apache License 2.0

OpenStack Heat OpenStack Heat is an orchestration service designed to automate the deployment and management of cloud applications on OpenStack-based infrastructures. It provides a declarative model for describing resources and their relationships, enabling repeatable provisioning across compute, storage, and networking components. Heat ties into multiple OpenStack Foundation projects and external technologies to coordinate lifecycle operations such as create, update, and delete.

Overview

Heat functions as an orchestration engine within the OpenStack ecosystem, exposing APIs that accept templates to instantiate stacks composed of resources from projects such as OpenStack Nova, OpenStack Neutron, and OpenStack Cinder. Its template-driven approach aligns with infrastructure-as-code practices popularized by tools linked to companies and organizations like Amazon Web Services, HashiCorp, and Google Cloud Platform while remaining tailored to the architecture of OpenStack. Heat supports complex dependency graphs, parameterization, and stack policies to manage updates and rollbacks, interoperating with provisioning and configuration tools such as Ansible, Chef (software), and Puppet.

Architecture

Heat's architecture separates orchestration logic, a template parser, and drivers that communicate with resource providers. The core components include the Heat API service, the Heat engine, a database for persistent stack state, and workers that enact resource operations. Communication relies on message-queue systems like RabbitMQ or Apache Kafka in deployments used by organizations such as Red Hat and Canonical Ltd.. The engine delegates lower-level actions to resource plugins and cloud provider drivers which call services including OpenStack Keystone for authentication, OpenStack Glance for image delivery, and OpenStack Swift for object storage. Heat can also integrate with metadata services and remote orchestration endpoints in hybrid scenarios involving vendors like VMware and institutions such as NASA.

Orchestration Templates and HOT

Heat Orchestration Template (HOT) is the native declarative template language for Heat, designed to express resources, outputs, parameters, and mappings. HOT templates are comparable in intent to formats used by AWS CloudFormation and influenced by standards promoted by groups such as the OpenStack Foundation community. Templates define resource types for services across the OpenStack landscape including flavors from OpenStack Nova, networks from OpenStack Neutron, and volumes from OpenStack Cinder. HOT supports intrinsic functions for joins, references, and attribute lookups, enabling integration with configuration management systems like SaltStack and CI/CD platforms such as Jenkins. Alternative template formats and translation layers exist to map formats from vendors like Microsoft and projects such as Kubernetes via adapters.

Deployment and Integration

Deployment of Heat is commonly managed by distribution vendors and system integrators including Red Hat, SUSE, Canonical Ltd., and cloud providers operating offerings similar to Rackspace. Heat is packaged to work with deployment tools like TripleO and OpenStack-Ansible, and can be configured for high availability using databases such as PostgreSQL and clustering technologies from Pacemaker. Integration scenarios often include identity federation with Keycloak or OpenID Connect providers, logging and monitoring with stacks that include Prometheus and ELK Stack, and policy enforcement leveraging OpenStack Keystone roles. Hybrid deployments pair Heat with external orchestration systems from vendors like BMC Software or research institutions such as Lawrence Livermore National Laboratory for specialized workflows.

Use Cases and Workflows

Common use cases for Heat include automated provisioning of multi-tier web applications, lifecycle management for telecommunication network functions used by operators such as AT&T and Verizon, and reproducible research environments at universities such as Massachusetts Institute of Technology and Stanford University. Workflows employ templates to create stacks that instantiate virtual machines, networks, load balancers, and block storage, then call configuration management tools to finalize application setup. Continuous delivery pipelines orchestrate stack updates, rollback scenarios, and blue-green deployments with orchestration patterns inspired by practices at Netflix and Spotify. Heat also supports nested stacks for modular compositions used by enterprises like IBM and government agencies including European Space Agency.

Security and Access Control

Heat relies on OpenStack Keystone for authentication and token-based access control, integrating with identity providers and directory services such as FreeIPA and Active Directory. Role-based policies govern who may create, update, or delete stacks, and resource-level policies can limit operations on specific services like OpenStack Nova or OpenStack Neutron. Secure deployments use TLS certificates from authorities like Let's Encrypt or enterprise PKI systems issued by organizations such as DigiCert, and follow hardening guidelines from vendors including Red Hat and standards bodies like ISO for operational security. Audit trails are typically recorded through logging systems such as Auditd and centralized collectors including Splunk.

Development and Community

Heat is developed within the OpenStack Foundation community with contributions from corporations, independent developers, and research groups such as NASA and Fujitsu. The project follows governance, release, and contribution models coordinated at summits and working groups where participants from companies like Red Hat, IBM, Cisco, and Huawei collaborate. Development workflows use tools including Gerrit, Git, and continuous integration provided by the OpenStack Zuul system. The community maintains documentation, reference templates, and implementer guides used by educational institutions like University of California, Berkeley and training organizations such as Linux Foundation.

Category:OpenStack