在OpenStack Heat中，如何编写YAML格式模板来部署一个包含Web服务器和数据库服务的环境？

要使用OpenStack Heat的YAML格式模板部署一个包含Web服务器和数据库服务的环境，首先需要了解Heat Orchestration Template (HOT)的基本结构和语法。HOT模板允许定义一个栈，这个栈可以包含多个资源，如虚拟机实例、网络和存储等。以下是一个简化版的YAML模板示例，用于部署一个简单的Web服务器环境，并在其上配置数据库服务：

参考资源链接：[OpenStack Heat模板与常用命令详解](https://wenku.csdn.net/doc/3z0888kyav?spm=1055.2569.3001.10343)

heat_template_version: 2013-05-23

description: >
  A basic HOT template for deploying a LAMP stack in OpenStack.

resources:
  web_server:
    type: OS::Nova::Server
    properties:
      name: web_server
      image: { get_param: WebServerImage }
      flavor: { get_param: WebServerFlavor }
      networks:
        - network: { get_param: WebServerNetwork }
      user_data: |
        #!/bin/bash
        apt-get update
        apt-get install -y lamp-server^ python3-pip
        pip3 install flask
        # Configuring the database server environment (example)
        echo 'CREATE DATABASE IF NOT EXISTS sampledb;' | mysql -u root -p$DB_PASSWORD
        # Setting up the web server (example)
        echo 'Web server has been setup!' > /var/www/html/index.html

  database_server:
    type: OS::Nova::Server
    properties:
      name: database_server
      image: { get_param: DBServerImage }
      flavor: { get_param: DBServerFlavor }
      networks:
        - network: { get_param: DBServerNetwork }
      user_data: |
        #!/bin/bash
        apt-get update
        apt-get install -y mysql-server
        echo 'bind-address = ***.*.*.*' >> /etc/mysql/***f
        service mysql start
        # Creating the database (example)
        mysql -u root -e 'CREATE DATABASE IF NOT EXISTS sampledb;'
        mysql -u root -e 

参考资源链接：[OpenStack Heat模板与常用命令详解](https://wenku.csdn.net/doc/3z0888kyav?spm=1055.2569.3001.10343)