python实现snmp_trap联动QOS策略

目前在杭州与上海间有两条带宽各为1G的线路，当其中一条线路断开后，流量会自动切换到另一条线路。MASTER线路在正常情况跑非spark间跨机房流量，平均流量在250Mb,峰值500M。SPARK线路正常情况跑跨机房spark与spark间的流量，平均流量小，峰值为跑满1G。

当前MASTER线路单IP限流250Mb,当spark线路断开后，流量切到master线路，自动进入400M上限限速，保证MASTER正常业务最小有600M可用带宽。因为master线路间的流量涉及IP广，无法提前标记流量，导致无法对MASTER流量做预置的QOS，同时要保证SPARK线路在两条线路都正常时，spark线路可以尽最大带宽跑流量。因当前网络设备不支持联动QOS策略，需要借助其它工具实现。跨机房QOS自动化是解决当前MASTER线路断开后流量切到SPARK线路，刚好SPARK线路流量正在满带宽在跑，MASTER流量无法得到保障问题。

设计思路：

在杭州端的设备上开启SNMP-TRAP,并在杭州机房布署，SNMP接收服务器。当接收到MASTER线路断开的NQA报警后，服务器自动登陆到设备启用SPARK线路上的限速策略。当接收到MASTER线路恢复正常报警后，服务器自动登陆到设备取消限速策略。

具体实施：

网络设备端：开启SNMP-TRAP,并放行到接收服务器的安全策略。

服务器端：

1、环境准备，需要用到的包：pysnmp,paramiko, twisted,time

2、服务端代码：

from twisted.internet import reactor

from pysnmp.entity import engine, config

from pysnmp.carrier.twisted.dgram import udp

from pysnmp.entity.rfc3413 import ntfrcv

import paramiko

import time

#device ip username and passwd

username = "*****" 

passwd = "******"

ip = '192.168.45.36'

#comands   

cmdup = ['sys','traffic-policy','rule name spark_hz>sh','disable','y',' rule name spark_sh>hz','disable','y']

cmddown = ['sys','traffic-policy','rule name spark_hz>sh','enable','rule name spark_sh>hz','enable']

#ssh device

def ssh2(ip,username,passwd,cmd):

    try:

        ssh = paramiko.SSHClient()

        ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())

        ssh.connect(ip,22,username,passwd,timeout=5)

        ssh_shell = ssh.invoke_shell()

        print ssh_shell.recv(1024)

        for m in cmd:

            res = ssh_shell.sendall(m+'\n')

            time.sleep(float(1))

        print ssh_shell.recv(1024)

        ssh.close()

    except :

        print '%s\tError\n'%(ip)

# Create SNMP engine with autogenernated engineID and pre-bound

# to socket transport dispatcher

snmpEngine = engine.SnmpEngine()

# Transport setup

# UDP over IPv4, first listening interface/port

config.addTransport(

    snmpEngine,

    udp.domainName + (1,),

    udp.UdpTwistedTransport().openServerMode(('0.0.0.0', 162))

)

# SNMPv1/2c setup

# SecurityName <-> CommunityName mapping

config.addV1System(snmpEngine, 'my-area', 'public')

# Callback function for receiving notifications

# noinspection PyUnusedLocal,PyUnusedLocal,PyUnusedLocal

def cbFun(snmpEngine, stateReference, contextEngineId, contextName,

          varBinds, cbCtx):

#Do what you want to do

     for  name, val in varBinds:

         if  val.prettyPrint()=='hz_sh_master':

               for name, val in varBinds:

                    if  val.prettyPrint()=='down':

                         print "down"

                         cmd=cmddown

                         ssh2(ip,username,passwd,cmd)

                    elif  val.prettyPrint()=='up':

                         print "up"

                         cmd=cmdup

                         ssh2(ip,username,passwd,cmd)

                    else:

                         pass

         else:

               pass

# Register SNMP Application at the SNMP engine

ntfrcv.NotificationReceiver(snmpEngine, cbFun)

# Run Twisted main loop

reactor.run()

# Register SNMP Application at the SNMP engine

ntfrcv.NotificationReceiver(snmpEngine, cbFun)

# Run Twisted main loop

reactor.run()

测试结果：

[root@192-168-56-48 snmptrap]# python snmptrap.py 

down

*************************************************************************
* Copyright (C) 2013-2017 Huawei Technologies Co., Ltd. *
* All rights reserved. *
* Without the owner's prior written consent, *
* no decompiling or reverse-engineering shall be allowed. *
*************************************************************************

Info: The max number of VTY users is 10, and the number
of current VTY users on line is 2.
The current login time is 2018-04-18 00:15:13+08:00.
HRP_M<XS-FW_ZX_Master>sys
Enter system view, return user view with Ctrl+Z.
HRP_M[XS-FW_ZX_Master]traffic-policy (+B)
HRP_M[XS-FW_ZX_Master-policy-traffic]rule name spark_hz>sh (+B)
HRP_M[XS-FW_ZX_Master-policy-traffic-rule-spark_hz>sh]enable (+B)
Info: The policy is enabled successfully. 
HRP_M[XS-FW_ZX_Master-policy-traffic-rule-spark_hz>sh]rule name spark_sh>hz (+B)
HRP_M[XS-FW_ZX_Master-policy-traffic-rule-spark_sh>hz]enable (+B)
Info: The policy is enabled successfully. 
HRP_M[XS-FW_ZX_Master-policy-traffic-rule-spark_sh>hz]

up

*************************************************************************
* Copyright (C) 2013-2017 Huawei Technologies Co., Ltd. *
* All rights reserved. *
* Without the owner's prior written consent, *
* no decompiling or reverse-engineering shall be allowed. *
*************************************************************************

Info: The max number of VTY users is 10, and the number
of current VTY users on line is 2.
The current login time is 2018-04-18 00:16:29+08:00.
HRP_M<XS-FW_ZX_Master>sys
Enter system view, return user view with Ctrl+Z.
HRP_M[XS-FW_ZX_Master]traffic-policy (+B)
HRP_M[XS-FW_ZX_Master-policy-traffic]rule name spark_hz>sh (+B)
HRP_M[XS-FW_ZX_Master-policy-traffic-rule-spark_hz>sh]disable (+B)
Warning: This command will invalidate the rule. Continue?[Y/N]y
Info: The policy is disabled successfully. 
HRP_M[XS-FW_ZX_Master-policy-traffic-rule-spark_hz>sh] rule name spark_sh>hz (+B)
HRP_M[XS-FW_ZX_Master-policy-traffic-rule-spark_sh>hz]disable (+B)
Warning: This command will invalidate the rule. Continue?[Y/N]y
Info: The policy is disabled successfully. 
HRP_M[XS-FW_ZX_Master-policy-traffic-rule-spark_sh>hz]