What are Heat templates?

In order to use Heat, text-based templates written in the YAML format are necessary. These templates are generally referred to as HOT (Heat Orchestration Templates), but in this document they are referred to as Heat templates.

YAML is a format for expressing structured data. Heat templates described in the YAML format are based on the format introduced in "HEAT Orchestration Template format". Each section is used to describe resources, parameters, etc., and a single template describes the configuration of an entire system.

Expressing these in highly readable YAML makes it easy to manage and modify system configurations.

Also, the fact that they are text based makes them easy to reuse.

Based on the content defined in the Heat template, the various resources are created on IaaS. This group of resources is referred to as a "stack".

Heat templates are text-based templates that are used to perform the definition, creation, and management of stacks.