摘要：
type=13&gid=199&msg=%s“%infotry:r=requests.getexcept:passif_name__==”__main__“：TAG=0#标志位，0正常，其他异常DNS=[”202.106.0.20“，”119.29.29.29“，”223.5.5.5“]obj=DnsHelper（）whileTrue：foriinrange:#状态是否为0两次，0正常或其他异常状态=obj.checkStatussprintifstatus！
#!/usr/bin/env python # coding=utf-8 # hexm@2016-02-14 import time import requests import paramiko import subprocess import requests HOST = ( "10.88.2.182:22",
"10.88.2.183:22",
"10.88.2.184:22"
)
class DnsHelper(object): def checkStatus(self, dns): ''' 检查状态 ''' status = subprocess.call('/usr/bin/dig www.baidu.com @%s +time=1 &> /dev/null' % dns, shell=True) return status def modifyStatus(self): NS = "nameserver %s nameserver %s nameserver %s" % (DNS[0], DNS[1], DNS[2]) cmd = "echo "%s" > /etc/resolv.conf" % NS self.exec_command(cmd) def exec_command(self, cmd): ''' 远程连接修改 ''' private_key = paramiko.RSAKey.from_private_key_file('/root/.ssh/id_rsa') ssh = paramiko.SSHClient() ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy()) for host in HOST: h,p = host.strip().split(':') try: ssh.connect(hostname=h, port=int(p), username='root', pkey=private_key, timeout=1) stdin, stdout, stderr = ssh.exec_command(cmd) except: continue ssh.close() self.alarm("切换dns为%s成功" % DNS[0]) def alarm(self, info): url = "http://alarm.mingxiao.com/alarm/index.php?type=13&gid=199&msg=%s" % info try: r = requests.get(url) except: pass if __name__ == "__main__": TAG = 0 # 标志位，0正常，其他不正常 DNS = ["202.106.0.20", "119.29.29.29", "223.5.5.5"] obj = DnsHelper() while True: for i in range(2): # 两次次状态是否为0， 0正常，其他不正常 status = obj.checkStatus(DNS[0]) print(status,TAG,DNS) if status != 0: TAG += 1 time.sleep(10) if TAG != 0: # 检测一次不正常，切换dns TAG = 0 obj.alarm('DNS %s 检测不正常,正在切换' % DNS[0]) DNS.append(DNS[0]) DNS.remove(DNS[0]) # 不正常的DNS放到末尾， status = obj.checkStatus(DNS[0]) # 检查新DNS是否正常 if status == 0: # 正常则切换dns obj.modifyStatus() #TAG = 0 time.sleep(300)