Writing templates
The two core concepts to get started with Heat are stacks and templates. A stack is a collection of resources related to one another and launched by way of a template. A template is a text document definition of a stack. To launch a Heat stack, a Heat template is launched. Let's look at both of these in more depth, starting with templates.
Before we can launch a stack, we need a template that will define the stack. There are two template formats that you can use to launch a stack in Heat. One is the AWS CloudFormation template format. If you have ever used CloudFormation in Amazon Web Services (AWS), then you will be familiar with this template format. Heat templates are very similar to those used within AWS, and add additional capabilities within OpenStack. The second format is the Heat Orchestration Template (HOT). HOT is a native Heat template format that is written in the YAML Ain't Markup Language syntax. For more examples of both, visit the Heat-templates GitHub repository...
