OpenStack入门之九:使用REST API启动虚拟机实例
1. 简介
上文OpenStack入门之八:使用python SDK代码启动虚拟机实例我们使用python SDK的代码来启动一个虚拟机实例。本文将演示如何使用REST API来启动一个虚拟机实例。
如果你不知道什么是REST请参考这篇博文，理解RESTful架构
从上文OpenStack入门之八:使用python SDK代码启动虚拟机实例我们知道要想创建一个虚拟机，至少知道三个参数，虚拟机名称，镜像名称以及类型模板(flavor)。所以我们首先要获取image ID及flavor ID,但是要得到这些资源，首先要获取TOKEN数据以及NOVA的URL地址。
2. 引用库文件
那么通过什么工具来与openstack API 通讯呢，这里我们用到了PYHON的标准库urllib2,另外我们使用JSON格式来传递数据，所以还要引用JSON库。
import json
import urllib2
3. 获取token数据
我们通过POST用户名密码的方式获取token数据,这里简单起见直接定义。
auth = {"auth":{"identity":{"methods":["password"],"password":{"user":{"domain":{"id":"default"},"name":"demo","password":"passw0rd"}}},"scope":{"project":{"domain":{"id":"default"},"name":"demo"}}}}
URL地址简单起见，也直接定义，这两个参数后续可以定义在配置文件抓取
auth_url = 'http://192.168.199.20:35357/v3/'
现在我们可以获取token数据了。
1 | def token_post(auth,auth_url): |
4. 获取NOVA URL地址
通过token返回的数据，我们可以直接筛选出NOVA的URL地址
1 | def get_nova_endpoint(response): |
5. 获取image ID
通过image名字获取iamge ID
1 | def get_image_id(novaurl,tokenid,imagename): |
6. 获取flavor ID
通过flavor名字获取flavor ID
1 | def get_flavor_id(novaurl,tokenid,flavorname): |
7. 创建虚拟机
现在我们可以创建虚拟机了。
1 | def create_vmserver(novaurl,tokenid,vmname,imange_id,flaver_id): |
8. 查看结果
运行源代码
我们查看instance，看到test1已经创建。
本文参考
http://developer.openstack.org/api-ref/compute/?expanded=create-server-detail
附整个源代码。
import json
import urllib2
def byteify(input):
if isinstance(input, dict):
return {byteify(key): byteify(value) for key, value in input.iteritems()}
elif isinstance(input, list):
return [byteify(element) for element in input]
elif isinstance(input, unicode):
return input.encode('utf-8')
else:
return input
def token_post(auth,auth_url):
headers = {"Content-type":"application/json","Accept": "application/json;charset=UTF-8"}
token_url = auth_url+"auth/tokens"
req = urllib2.Request(token_url, auth, headers)
response = urllib2.urlopen(req)
token = response.info().getheader("X-Subject-Token")
response.encoding='utf-8'
response_json = json.loads(response.read())
response_json = byteify(response_json)
response_json['authtoken'] = token
return response_json
def get_nova_endpoint(response):
services = response['token']['catalog']
for i in range(0, len(services)):
if services[i]['name'] == 'nova':
nova_endpoint = services[i]['endpoints'][0]['url']
return nova_endpoint
def get_image_id(novaurl,tokenid,imagename):
servers_url = novaurl+'/'+'images'
req = urllib2.Request(servers_url)
req.add_header('X-Auth-Token', tokenid)
response = urllib2.urlopen(req)
services = json.loads(response.read())['images']
for i in range(0, len(services)):
if services[i]['name'] == imagename:
image_id = services[i]['id']
return image_id
def get_flavor_id(novaurl,tokenid,flavorname):
servers_url = novaurl+'/'+'flavors'
req = urllib2.Request(servers_url)
req.add_header('X-Auth-Token', tokenid)
response = urllib2.urlopen(req)
services = json.loads(response.read())['flavors']
for i in range(0, len(services)):
if services[i]['name'] == flavorname:
flavor_id = services[i]['id']
return flavor_id
def create_vmserver(novaurl,tokenid,vmname,imange_id,flaver_id):
headers = {"Content-type":"application/json","Accept": "application/json;charset=UTF-8","X-Auth-Token":tokenid}
#print headers
servers_url = novaurl+"/servers"
#print servers_url
body={"server": {"name": vmname, "imageRef": imange_id, "flavorRef": flaver_id}}
body=json.dumps(body)
#print body
req = urllib2.Request(servers_url,body,headers)
response = urllib2.urlopen(req)
response_json = json.loads(response.read())
return response_json
if __name__ == '__main__':
auth = {"auth":{"identity":{"methods":["password"],"password":{"user":{"domain":{"id":"default"},"name":"demo","password":"passw0rd"}}},"scope":{"project":{"domain":{"id":"default"},"name":"demo"}}}}
auth = json.dumps(auth)
auth_url = 'http://192.168.199.20:35357/v3/'
response = token_post(auth,auth_url)
#print response
tokenid = response['authtoken']
novaurl = get_nova_endpoint(response)
#print novaurl
imange_id=get_image_id(novaurl,tokenid,'cirros-0.3.4-x86_64-uec')
flaver_id=get_flavor_id(novaurl,tokenid,'m1.tiny')
print create_vmserver(novaurl,tokenid,'test1',imange_id,flaver_id)