Heat模板全称为heat orchestration template，简称为HOT。
1 典型Heat模板结构
heat_template_version: 2015-04-30
description:# a description of the template
parameter_groups:# a declaration of input parameter groups and order
parameters:# declaration of input parameters
resources:# declaration of template resources
outputs:# declaration of output parameters2 heat_template_version
每个HOT需要包含 heat_template_version 字段，指明所使用的 HOT 版本。
每个版本支持的内置方法不同，比如2016-04-08版本支持的内置方法如下：
digest、 get_attr、get_file、get_param、get_resource、list_join、
map_merge、repeat、resource_façade、str_replace、str_split
3 parameter groups
用于指定参数的顺序，每个参数只能与指定的group关联一次。
parameter_groups:
- label: <human-readable label of parameter group>description: <description of the parameter group>parameters:- <param name>- <param name>4 parameter
parameters:<param name>:type: <string | number | json | comma_delimited_list | boolean>label: <human-readable name of the parameter>description: <description of the parameter>default: <default value for parameter>hidden: <true | false>constraints:<parameter constraints>immutable: <true | false>示例：
parameters:user_name:type: stringlabel: User Namedescription: User name to be configured for the applicationport_number:type: numberlabel: Port Numberdescription: Port number to be configured for the web serverparameter type:
Type | Description | Examples |
string | A literal string. | “String param” |
number | An integer or float. | “2”; “0.2” |
comma_delimited_list | An array of literal strings that are separated by commas. The total number of strings should be one more than the total number of commas. | [“one”, “two”]; “one, two”; Note: “one, two” returns [“one”, ” two”] |
json | A JSON-formatted map or list. | {“key”: “value”} |
boolean | Boolean type value, which can be equal “t”, “true”, “on”, “y”, “yes”, or “1” for true value and “f”, “false”, “off”, “n”, “no”, or “0” for false value. | “on”; “n” |
hidden：隐藏用户输入的信息，如密码，将 hidden 属性置为 true。
constraints：已有的内置参数：OS::stack_name、OS::stack_id、OS::project_id。
constraints:- <constraint type>: <constraint definition>description: <constraint description>5 resources
resources:<resource ID>:type: <resource type>properties:<property name>: <property value>metadata:<resource specific metadata>depends_on: <resource ID or list of ID>update_policy: <update policy>deletion_policy: <deletion policy>示例：
resources:my_instance:type: OS::Nova::Serverproperties:flavor: m1.smallimage: F18-x86_64-cfntools资源依赖的示例：
resources:server1:type: OS::Nova::Serverdepends_on: [ server2, server3 ]server2:type: OS::Nova::Server6 outputs
outputs:<parameter name>:description: <description>value: <parameter value> 示例：
outputs:instance_ip:description: IP address of the deployed compute instancevalue: { get_attr: [my_instance, first_address] } 编者注：本文来自OpenStack开源团队工程师陈曾
