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Heat


OpenStack Orchestration

The mission of the OpenStack Orchestration program is to create a human- and machine-accessible service for managing the entire lifecycle of infrastructure and applications within OpenStack clouds.

Heat

Heat is the main project in the OpenStack Orchestration program. It implements an orchestration engine to launch multiple composite cloud applications based on templates in the form of text files that can be treated like code. A native Heat template format is evolving, but Heat also endeavours to provide compatibility with the AWS CloudFormation template format, so that many existing CloudFormation templates can be launched on OpenStack. Heat provides both an OpenStack-native ReST API and a CloudFormation-compatible Query API.

Why ‘Heat’? It makes the clouds rise!

How it works

  • A Heat template describes the infrastructure for a cloud application in a text file that is readable and writable by humans, and can be checked into version control, diffed, &c.
  • Infrastructure resources that can be described include: servers, floating ips, volumes, security groups, users, &c.
  • Heat also provides an autoscaling service that integrates with Ceilometer, so you can include a scaling group as a resource in a template.
  • Templates can also specify the relationships between resources (e.g. this volume is connected to this server). This enables Heat to call out to the OpenStack APIs to create all of your infrastructure in the correct order to completely launch your application.
  • Heat manages the whole lifecycle of the application - when you need to change your infrastructure, simply modify the template and use it to update your existing stack. Heat knows how to make the necessary changes. It will delete all of the resources when you are finished with the application, too.
  • Heat primarily manages infrastructure, but the templates integrate well with software configuration management tools such as Puppet and Chef. The Heat team is working on providing even better integration between infrastructure and software.

Architecture

Heat comprises a number of Python applications:

heat

The heat tool is a CLI which communicates with the heat-api to execute AWS CloudFormation APIs. Of course this is not required—developers could also use the Heat APIs directly.

heat-api

The heat-api component provides an OpenStack-native ReST API that processes API requests by sending them to the heat-engine over RPC.

heat-api-cfn

The heat-api-cfn component provides an AWS-style Query API that is compatible with AWS CloudFormation and processes API requests by sending them to the heat-engine over RPC.

heat-engine

The heat engine does the main work of orchestrating the launch of templates and providing events back to the API consumer.

Development

Getting Started Guides

There are getting started guides for several distributions in the Heat Documentation

Other Links

heat-core Blogs & Presentation Material

Get involved

IRC

The developers use IRC in #heat on Freenode for development discussion.

Meetings

Meetings are held on IRC in #openstack-meeting on Freenode. See the Heat agenda page for times and details.

Mailing list

Discussions about Heat happens on the openstack-dev mailing list. Please use the tag [Heat] in the subject line for new threads.