Juniper SNMP Migrations

This example will show how to use the PyEZ plugin for Nornir to

  1. build a NETCONF connection to a remote device
  2. validate that SNMPv3 is not running
  3. configure SNMPv3 parameters
  4. close the connection

? Workflow

We have provided a Poetry lock file to make life simple when managing Python packages and virtual environments. Within the virtual vironment, there will be a package called Invoke that will help us run our script with a simple command.

The workflow will look like this:

  1. Install Poetry (one-time operation)
  2. Have Poetry install your Python packages in a virtual environment (one-time operation)
  3. Activate your new virtual environment with Poetry
  4. Run locally or within a container using the Invoke package

? Create and Activate your Python environment (one time operation)

  1. install poetry package to manage our Python virtual environment
curl -sSL | python -
  1. install our Python dependencies
poetry install
  1. activate your Python virtual environment
poetry shell

Executing the script

  1. run your Nornir script locally

cd files/nornir

Using Docker

  1. build the container image with
invoke build
  1. run the Nornir script within the container
invoke nornir

⚙️ How it works

Let’s take a second to do a nice John Madden play-by-play on this script:

Importing the functionality of PyEZ and Nornir into our script

from nornir_pyez.plugins.tasks import pyez_rpc
from nornir import InitNornir
from rich import print
import os
  • We need to import the pyez_rpc method from Nornir’s PyEZ plugin into our script
  • InitNornir will import the core functionality of Nornir
  • rich will make things pretty when we print the output
  • import os is just to allow us to shortcut the path of your directory

Defining parameters

script_dir = os.path.dirname(os.path.realpath(__file__))

nr = InitNornir(config_file=f"{script_dir}/config.yaml")

firewall = nr.filter(name="juniper-srx-garage0")

extras = {
    "less-than": "1"
  • create an object called script_dir and set it to our local directory
  • nr is created by instantiation the InitNornir class and passing our config file into it
  • we filter out a single device with the nr.filter method and passing a hostname
  • any extra parameters for our RPC call will be defined here in a key/value structure

Sending our API call

response =
    task=pyez_rpc, func='get-security-policies-hit-count', extras=extras
  • create a new object called response and setting it equal to the response of our API call
  • the run function was imported when we created an object firewall based on the InitNornir class
  • within run, we pass the task as a pyez_rpc, our RPC API call, and extra parameters


for dev in response:

Loop over the response object, which is an AggregatedResult that behaves like a list. There is a response object for each device in inventory

? Screenshot

? Additional Notes

? Python

You are strongly recommended to using a Python Virtual Environment any and everywhere possible. You can really mess up your machine if you’re too lazy and say “ehh, that seems like it’s not important”. It is. If it sounds like I’m speaking from experience, I’ll never admit to it.

If you’re interested in learning more about setting up Virtual Environments, I encourage you to read a few blogs on the topic. A personal recommendation would be

? Docker

If you are unsure if Docker is installed on your computer, then it’s probably safe to suggest that it’s not. If you’re interested in learning more about the product, I encourage you to read a few blogs on the topic. A personal recommendation would be Digital Ocean

Some of the goodies placed in the docker folder are not relevant to our use case with Python. Feel free to delete them as you see fit, I simply wanted to share with you my Docker build process for all Juniper automation projects (including those based on Ansible). The world is your oyster and I won’t judge you on whatever direction you take.

? Dependencies

Refer to the file located at files/docker/requirements.txt


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