前言

heat是对openstack资源的编排工具，编排可以理解为自动化。
在heat中，将一次编排任务称之为stack。创建编排就是创建一个stack。

演示使用 python-heatclient 创建特定需求的虚拟机。
涉及非常多的新知识，这篇文章只能至简的介绍使用。

环境

python2
openstack版本：queens
模板格式：HOT

正文

这里可以拆分为3个部分：

python-heatclient：主体运行程序
yaml文件：定义资源的规格，可以编写简单的逻辑。
虚拟机执行脚本：虚拟机开机时执行的脚本，这个可以整合在yaml文件中，也可以独立出来。

总体流程：

准备好配置文件，参数
创建stack

运行一个实例

准备yaml文件。
yaml文件直接引用官方给出的例子，不做任何修改。
地址：
https://github.com/openstack/heat-templates/blob/master/hot/servers_in_existing_neutron_net.yaml
贴出其中的内容：

heat_template_version: 2013-05-23

description: >
  HOT template to deploy two servers into an existing neutron tenant network and
  assign floating IP addresses to each server so they are routable from the
  public network.
parameters:
  key_name:
    type: string
    description: Name of keypair to assign to servers
  image:
    type: string
    description: Name of image to use for servers
  flavor:
    type: string
    description: Flavor to use for servers
  public_net_id:
    type: string
    description: >
      ID of public network for which floating IP addresses will be allocated
  private_net_id:
    type: string
    description: ID of private network into which servers get deployed
  private_subnet_id:
    type: string
    description: ID of private sub network into which servers get deployed

resources:
  server1:
    type: OS::Nova::Server
    properties:
      name: Server1
      image: { get_param: image }
      flavor: { get_param: flavor }
      key_name: { get_param: key_name }
      networks:
        - port: { get_resource: server1_port }

  server1_port:
    type: OS::Neutron::Port
    properties:
      network_id: { get_param: private_net_id }
      fixed_ips:
        - subnet_id: { get_param: private_subnet_id }
      security_groups: [{ get_resource: server_security_group }]

  server1_floating_ip:
    type: OS::Neutron::FloatingIP
    properties:
      floating_network_id: { get_param: public_net_id }
      port_id: { get_resource: server1_port }

  server2:
    type: OS::Nova::Server
    properties:
      name: Server2
      image: { get_param: image }
      flavor: { get_param: flavor }
      key_name: { get_param: key_name }
      networks:
        - port: { get_resource: server2_port }

  server2_port:
    type: OS::Neutron::Port
    properties:
      network_id: { get_param: private_net_id }
      fixed_ips:
        - subnet_id: { get_param: private_subnet_id }
      security_groups: [{ get_resource: server_security_group }]

  server2_floating_ip:
    type: OS::Neutron::FloatingIP
    properties:
      floating_network_id: { get_param: public_net_id }
      port_id: { get_resource: server2_port }

  server_security_group:
    type: OS::Neutron::SecurityGroup
    properties:
      description: Add security group rules for server
      name: security-group
      rules:
        - remote_ip_prefix: 0.0.0.0/0
          protocol: tcp
          port_range_min: 22
          port_range_max: 22
        - remote_ip_prefix: 0.0.0.0/0
          protocol: icmp

outputs:
  server1_private_ip:
    description: IP address of server1 in private network
    value: { get_attr: [ server1, first_address ] }
  server1_public_ip:
    description: Floating IP address of server1 in public network
    value: { get_attr: [ server1_floating_ip, floating_ip_address ] }
  server2_private_ip:
    description: IP address of server2 in private network
    value: { get_attr: [ server2, first_address ] }
  server2_public_ip:
    description: Floating IP address of server2 in public network
    value: { get_attr: [ server2_floating_ip, floating_ip_address ] }

创建一个template文件，将内容完整的复制进去：

vim servers_in_existing_neutron_net.yaml

创建stack
这个template文件大体是创建了一个带浮动ip的虚拟机，并且创建了一个安全组绑定到虚拟机端口上。

创建python 程序：
vim client.py

# coding:utf8

from keystoneauth1 import session
from keystoneauth1.identity import v3
from heatclient import client as heat_client

# 注意替换认证信息
auth = v3.Password(
            auth_url="http://192.168.110.10:35357/v3",
            username="admin",
            password="qwe",
            project_id="97eaa64704bd4f549f3abf99a6decdc1",
            user_domain_id='default')
sess = session.Session(auth=auth)


hc = heat_client.Client('1', session=sess)

# 注意替换模板路径
template_path = "./servers_in_existing_neutron_net.yaml"

# 注意替换 镜像等信息。这里的 parameters 就是模板中定义的参数
parameters = {
        "key_name": "be8ee056ea274d45a1fd97bfd36c2775_lzp",
        "image": "cirros",
        "flavor": "cc00d88f-9ed5-4012-9840-faf8add2873d",
        "public_net_id": "4955888e-1622-4a2b-88d7-2c58e092e7fa",
        "private_net_id": "77844f4d-0dd8-4532-bbaa-d17efd5a1895",
        "private_subnet_id": "9a7bfada-fd99-4ac4-a4a0-66e872019bc1"
}

template = open(template_path).read()
stack_name = "test1"

with open(template_path, "r") as f:
        stack = hc.stacks.create(
                stack_name=stack_name,
                template=f.read(),
                parameters=parameters
        )

print(stack)

运行即可。
可以通过命令行查看进度：

openstack stack list

image.png

扩展

outputs

在template中尾部定义了 outputs。用于保留这个stack的某些重要信息。不需要可以不定义。
代码参考：

stack_id = "4d05cb2d-76a0-4ca4-a484-494ddcdcd243"

# 列出output列表
outputs = hc.stacks.output_list(stack_id=stack_id)
print(outputs)

# 显示output中某个键值对
server1_public_ip = hc.stacks.output_show(stack_id=stack_id, output_key="server1_public_ip")
print(server1_public_ip)