Nornir - How to increase Netmiko/NAPALM connection timers

[Nick-Robinson]

Hi,

A Nornir newbie. I'm pulling an inventory of 300+ Cisco WAN routers from Netbox and i want to run commands against that inventory to either augment the Netbox data or build files that can be used by ELK to enrich data. All routers are using a central TACACS+ server and a significant proportion are connected over satellite. For those devices the round trip latency is at minimum 1/2 second for the ssh session to receive a prompt and the same again for authentication back to the TACACS+ server.

Everytime i run the script i have a different number of successes failures regardless of NAPALM or Netmiko. I can manually connect to any of the failed devices. All produce the paramiko/netmiko trace below. I've played about with the nornir run delay and loop options and the number of workers in the init statement. The best result i have managed is nearly 90% success by using a single worker.

I am not sure about NAPALM but from my reading I believe netniko gets it's 'conn_timer' from the host config? Can i get that from a netbox custom field and if so can i apply it to the InitNornir or Nornir run. What about NAPALM? If i can't adjust the timers is there an easy way to create a new inventory from the failed_hosts to have another attempt ?

Any help/pointers much appreciated, Nick

`Host 'bdr01-monuc-gom-DR': task 'Interface_Detail_Index' failed with traceback:
Traceback (most recent call last):
File "D:\Users\nrobinson\PycharmProjects\uo-utils\venv\lib\site-packages\netmiko\base_connection.py", line 935, in establish_connection
self.remote_conn_pre.connect(**ssh_connect_params)
File "D:\Users\nrobinson\PycharmProjects\uo-utils\venv\lib\site-packages\paramiko\client.py", line 412, in connect
server_key = t.get_remote_server_key()
File "D:\Users\nrobinson\PycharmProjects\uo-utils\venv\lib\site-packages\paramiko\transport.py", line 834, in get_remote_server_key
raise SSHException("No existing session")
paramiko.ssh_exception.SSHException: No existing session

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "D:\Users\nrobinson\PycharmProjects\uo-utils\venv\lib\site-packages\nornir\core\task.py", line 99, in start
r = self.task(self, **self.params)
File "D:\Users\nrobinson\PycharmProjects\uo-utils\venv\lib\site-packages\nornir_netmiko\tasks\netmiko_send_command.py", line 26, in netmiko_send_command
net_connect = task.host.get_connection(CONNECTION_NAME, task.nornir.config)
File "D:\Users\nrobinson\PycharmProjects\uo-utils\venv\lib\site-packages\nornir\core\inventory.py", line 494, in get_connection
self.open_connection(
File "D:\Users\nrobinson\PycharmProjects\uo-utils\venv\lib\site-packages\nornir\core\inventory.py", line 546, in open_connection
conn_obj.open(
File "D:\Users\nrobinson\PycharmProjects\uo-utils\venv\lib\site-packages\nornir_netmiko\connections\netmiko.py", line 59, in open
connection = ConnectHandler(**parameters)
File "D:\Users\nrobinson\PycharmProjects\uo-utils\venv\lib\site-packages\netmiko\ssh_dispatcher.py", line 326, in ConnectHandler
return ConnectionClass(*args, **kwargs)
File "D:\Users\nrobinson\PycharmProjects\uo-utils\venv\lib\site-packages\netmiko\cisco\cisco_ios.py", line 17, in init
return super().init(*args, **kwargs)
File "D:\Users\nrobinson\PycharmProjects\uo-utils\venv\lib\site-packages\netmiko\base_connection.py", line 350, in init
self._open()
File "D:\Users\nrobinson\PycharmProjects\uo-utils\venv\lib\site-packages\netmiko\base_connection.py", line 355, in _open
self.establish_connection()
File "D:\Users\nrobinson\PycharmProjects\uo-utils\venv\lib\site-packages\netmiko\base_connection.py", line 980, in establish_connection
raise NetmikoTimeoutException(msg)
netmiko.ssh_exception.NetmikoTimeoutException: Paramiko: 'No existing session' error: try increasing 'conn_timeout' to 10 seconds or larger.
`

[jchristopher327]

here's where you can set this timer.

ios:
  platform: "ios"
  port: 22
  connection_options:
    netmiko:
      extras:
        conn_timeout: 10