远程获取EC2虚拟机的IP地址

　　最近申请了个EC2虚拟机，可以免费使用720个小时，用来爬墙还是蛮方便的。但每次重新启动后虚拟机的IP都会发生变化，到管理页面上查询太麻烦，而且我不想申请弹性IP因为停止虚拟机后弹性IP不再使用，这样会被亚马逊惩罚的(每小时要付费0.01刀)。作为程序员，我们总是想化繁为简，写个小代码自动获得IP呗！

　　以前部署过Eucalyptus，它是亚马逊EC2的开源实现，用ec2tools可以启停虚拟机，看过代码发现它用python实现，用到了boto库。我自己也随便写了个。

__author__ = 'flyingzl'
import boto
from boto.ec2.regioninfo import RegionInfo

EC2_ACCESS_KEY = 'access_key'
EC2_SECRET_KEY = 'secret_key'
REGION_NAME = 'us-west-1'
REGION_ENDPOINT = 'ec2.us-west-1.amazonaws.com'
region = RegionInfo(name=REGION_NAME, endpoint=REGION_ENDPOINT)
conn = boto.connect_ec2(EC2_ACCESS_KEY, EC2_SECRET_KEY, region=region, is_secure=False)
reservations = conn.get_all_instances()

def operate(type=None):
    for reservation in reservations:
        for instance in reservation.instances:
            state = instance.state
            print "id:%s,state:%s,ip:%s"\
            % (instance.id, state, instance.ip_address)
            if type == 'start' and state == 'stopped':
                instance.start()
            elif type == 'stop' and state == 'running':
                instance.stop()
            else:
                print 'state:%s' % (instance.state)

operate('start')

如果知道虚拟的instance_id，可以更简单点：

#停止指定的虚拟机
conn.stop_instances(instance_ids='i-e28f92a6')
#启动指定的虚拟机
conn.start_instances(instance_ids='i-e28f92a6')

得到IP后我们就可以通过putty来进行端口转发了，但是每次修改IP后我们都得在putty里面重新配置IP，比较麻烦。为何不在修改IP后更新putty的配置信息呢？

putty的配置都存在注册表里面，我们更新下注册表即可。完整代码如下：

#coding=utf-8
__author__ = 'flyingzl'
import boto
from boto.ec2.regioninfo import RegionInfo
import _winreg  as winreg
import time

EC2_ACCESS_KEY = 'secret_key'
EC2_SECRET_KEY = 'secret_code'
REGION_NAME = 'us-west-1'
REGION_ENDPOINT = 'ec2.us-west-1.amazonaws.com'
PUTTY_LOCATION = 'Software\SimonTatham\PuTTY'
#设置putty中虚拟机的连接名为为ec2，其他童鞋可以改为自己的
PUTTY_SESSION = 'Sessions\ec2'
PUTTY_HOSTKEY = 'SshHostKeys'

region = RegionInfo(name=REGION_NAME, endpoint=REGION_ENDPOINT)
conn = boto.connect_ec2(EC2_ACCESS_KEY, EC2_SECRET_KEY, debug=0, region=region, is_secure=False)


#修改PUTTY在注册表保存的IP地址
def change_ip(ip):
    if ip is None:
        return
    key = winreg.OpenKey(winreg.HKEY_CURRENT_USER, PUTTY_LOCATION)
    session_key = winreg.OpenKey(key, PUTTY_SESSION, 0, winreg.KEY_ALL_ACCESS)
    host_key = winreg.OpenKey(key, PUTTY_HOSTKEY, 0, winreg.KEY_ALL_ACCESS)
    #获得注册表中ec2的ip地址
    hostname = winreg.QueryValueEx(session_key, 'HostName')[0]
    #修改注册表中的IP地址
    #HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\Sessions\ec2,HostName键
    winreg.SetValueEx(session_key, 'HostName', 0, winreg.REG_SZ, ip)
    #获取host_key下value的个数
    value_count = winreg.QueryInfoKey(host_key)[1]
    for index in range(value_count):
        key, value, type = winreg.EnumValue(host_key, index)
        if key.find(hostname) > -1:
            try:
                winreg.DeleteValue(host_key, key)
            except WindowsError:
                pass
                #HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\SshHostKeys,rsa2@22:ip键
            winreg.SetValueEx(host_key, 'rsa2@22:%s' % ip, 0, winreg.REG_SZ, value)
            break


def operate(type=None):
    instance_state = None
    instance_ip = None
    reservations = conn.get_all_instances(instance_ids='i-e28f92a6')
    for reservation in reservations:
        for instance in reservation.instances:
            instance_state = instance.state
            instance_ip = instance.ip_address
            print "id:%s,state:%s,ip:%s"% (instance.id, instance_state, instance_ip)
            if type == 'start' and instance_state == 'stopped':
                instance.start()
            elif type == 'stop' and instance_state == 'running':
                instance.stop()
            else:
                pass
    return instance_ip

def stop_vm():
    ip = operate(type='stop')
    if ip is not None:
        time.sleep(2)
        stop_vm()
    else:
        print 'stop vm successfully!'


def start_vm():
    ip = operate(type='start')
    if ip is None:
        time.sleep(1)
        start_vm()
    else:
        change_ip(ip)
        print 'start vm successfully!'

if __name__ == '__main__':
#    stop_vm()
    start_vm()