我最近接受了一次采访,被要求写一个代码登录到3台路由器中,然后每台路由器一次重新加载-在移动以重新加载下一个设备之前,检查BGP是否已建立并且接口是否已启动。我们提供了一个导入的模块,该模块可以SSH到路由器中并重新加载它。有人在想吗?我是Python的新手
尽管为SSH提供了一个模块,但我首先将其编码出来,这就是我很累的地方。只是为了了解路由器的工作方式以及我要检查的内容:
import socket
import paramiko
def run_ssh_command(username, password, host, command):
"""
Using paramiko to SSH into remote locations and run commands
"""
port = 22
s = paramiko.SSHClient()
s.set_missing_host_key_policy(paramiko.AutoAddPolicy())
try:
s.connect(host, port, username, password, look_for_keys=False, timeout=5.0)
except paramiko.AuthenticationException as e:
print("authentication failed: ", e)
s.close()
return
except socket.timeout as e:
print("socket timeout: ", e)
s.close()
return
except paramiko.SSHException as e:
print("SSH Exception: ", e)
s.close()
return
except socket.error as e:
print("socket error: ", e)
s.close()
return
(stdin, stdout, stderr) = s.exec_command(command)
print ("ran command ", command)
# for line in stdout.readlines():
# print(line)
s.close()
if __name__ == "__main__":
while True:
run_ssh_command("CompRouter", "backbonedevice", "10.10.10.25", "show ip bgp summary")
所以我的思路是将SSH连接到设备,发出“ show ip bgp summary”命令-该表通常如下所示:
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down Statd
10.10.10.2 4 65536 7 7 1 0 0 00:03:04 0
这个想法是要检查InQ / OutQ值是否为零或BGP邻居的非“ Down”状态,然后才重新加载下一个路由器。
尤其是在我被困的地方。给定这样的表,如何检查整个InQ / OutQ列(可能有多个邻居),然后采取必要的措施?
答案 0 :(得分:1)
选择使用napalm
和netmiko
-就像一种魅力:
from simplecrypt import encrypt, decrypt
from pprint import pprint
from netmiko import ConnectHandler
from napalm import get_network_driver
import json
#from time import time
import time
def read_device_data(devices_filename):
devices = {} #Create a dictionary for each IP's unique info
with open(devices_filename) as device_info:
for lines in device_info:
this_dev = lines.strip().split(',')
dev = {'ipaddr': this_dev[0],
'type': this_dev[1],
'name': this_dev[2]}
devices[dev['ipaddr']] = dev
print('Displaying info for all devices below: ')
pprint(devices)
return devices
#Create a function to decrypt and read file containing credentials encrypted in the format ip,username,password
def read_device_creds(device_cred_filename, key):
print('\n Decoding encrypted device credentials....')
with open(device_cred_filename, 'rb') as device_creds_file:
device_creds_decry = decrypt(key, device_creds_file.read())
device_creds_list = json.loads(device_creds_decry.decode('utf-8'))
pprint(device_creds_list)
print('\n Displaying device credentials in dictionary format:')
"""
Convert device_creds_list to dictionary using list comprehension
"""
device_creds_dict = {this_dev[0]: this_dev for this_dev in device_creds_list}
print(device_creds_dict)
return device_creds_dict
def check_BGP(net_device, cred):
print(f"Connecting to {net_device['ipaddr']} right now to check BGP status.....")
while True:
try:
driver = get_network_driver('ios')
iosv = driver(net_device['ipaddr'], cred[1], cred[2])
iosv.open()
except:
print('Waiting to establish a socket...')
else:
time.sleep(30)
ios_output = iosv.get_bgp_neighbors()
for k,v in ios_output.items():
for y in v.values():
if type(y) == dict:
for z in y.values():
print(f"BGP peer is up? {z['is_up']}")
return z['is_up'] == True
def reload(creds):
iosv_device = {
'device_type': 'cisco_ios',
'ip': creds[0],
'username': creds[1],
'password': creds[2]
}
net_connect = ConnectHandler(**iosv_device)
output = net_connect.send_command_timing('wr mem')
time.sleep(10)
output += net_connect.send_command_timing('reload')
output += net_connect.send_command_timing('y')
print(output)
def is_alive(alive_dev, alive_cred): #check if device is back online after reload
while True:
try:
driver = get_network_driver('ios')
iosvl2 = driver(alive_dev['ipaddr'], alive_cred[1], alive_cred[2])
iosvl2.open()
except:
print(f"Attempting to reconnect to {alive_cred[0]}")
else:
alive_output = iosvl2.is_alive()
print(alive_output)
return alive_output['is_alive'] == True
break
if __name__ == '__main__':
net_devices = read_device_data('devices_data')
net_creds = read_device_creds('encrypted_device_creds', 'cisco')
# starting_time = time()
for ipadd, device_info in net_devices.items():
print(net_devices.items())
while True:
print (f'Connecting to: {ipadd}')
if check_BGP(device_info, net_creds[ipadd]) == True:
print(f'Reloading {ipadd} now')
reload(net_creds[ipadd])
else:
print(f'Re-checking BGP on {ipadd}')
if is_alive(device_info, net_creds[ipadd]) == True and check_BGP(device_info, net_creds[ipadd]) == True:
print(f'{ipadd} back online and BGP OK!')
break
else:
print('Router down or BGP failed to reconverged; exiting script')
break
# print ('\n---- End get config sequential, elapsed time=', time() - starting_time)