如何在 python 中使用 netmiko 在多个 cisco 设备上执行 ssh

Question

I am trying run this below script for multiple devices and it is working only for last device according to below script.

Please can you verify the below script as I need to execute both device output using for loop statement.

from netmiko import ConnectHandler 
from getpass import getpass

password= getpass()

RTR_01 = {

         'device_type': 'cisco_ios',
         'host': '10.10.10.10',
         'username': 'admin',
         'password': password,
}

RTR_02 = { 'device_type': 'cisco_ios', 
           'host': '10.10.10.11', 
           'username': 'admin', 
           'password': password, }

device_list = [RTR_01,RTR_02] 

for device in device_list: print('Connecting to the device :' + device ['host']) 

net_connect = ConnectHandler(**device)

output = net_connect.send_command('show ip interface brief')
print(output)
output = net_connect.send_command('show version')
print(output)

Answer 1

I now how it working 100% correctly. I had tried net_connect.disconnect() with the appropriate indentations which didn't work because once you exit the indent for the loop, it automatically exits. The problem, silly as it is, was that I was still connected to the actual device and was receiving an error that I had overlooked complaining about not being able to create /var/home/myusername/.ssh

All I needed to do was issue the following command at the very end of the loop:

net_connect.write_channel('exit\\n')

Such as silly mistake and so much time wasted but the lesson was valuable! Maybe it can help someone else here.

Answer 2

You need these lines to indented within the for loop

net_connect = ConnectHandler(**device)

output = net_connect.send_command('show ip interface brief')
print(output)
output = net_connect.send_command('show version')
print(output)

Your code should look like this:

from getpass import getpass

from netmiko import ConnectHandler

password = getpass()

RTR_01 = {
    "device_type": "cisco_ios",
    "host": "10.10.10.10",
    "username": "admin",
    "password": password,
}

RTR_02 = {
    "device_type": "cisco_ios",
    "host": "10.10.10.11",
    "username": "admin",
    "password": password,
}

device_list = [RTR_01, RTR_02]

for device in device_list:
    print("Connecting to the device :" + device["host"])

    net_connect = ConnectHandler(**device)

    output = net_connect.send_command("show ip interface brief")
    print(output)
    output = net_connect.send_command("show version")
    print(output)

    net_connect.disconnect() # to clear the vty line when done

And this is a better version of your code that does the same exact thing:

from getpass import getpass

from netmiko import ConnectHandler

password = getpass()

ipaddrs = ["10.10.10.10", "10.10.10.11"]

# A list comprehension
devices = [
    {
        "device_type": "cisco_ios",
        "host": ip,
        "username": "admin",
        "password": password,
    }
    for ip in ipaddrs
]

for device in devices:
    print(f'Connecting to the device: {device["host"]}')

    with ConnectHandler(**device) as net_connect:  # Using Context Manager
        intf_brief = net_connect.send_command(
            "show ip interface brief"
        )  # Inside the connection
        facts = net_connect.send_command("show version")  # Inside the connection

        # Notice here I didn't call the `net_connect.disconnect()`
        # because the `with` statement automatically disconnects the session.

    # On this indentation level (4 spaces), the connection is terminated
    print(intf_brief)
    print(facts)

The outputs ( intf_brief and facts ) are printed outside the connection, because the session is not needed anymore to print any collected values.