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Mauricio Rojas#

Finding misconfigurations in your fabric using pyGNMI

Git Repo

Today, I'm sharing another piece of my experience from the NANOG88 conference where I had the privilege of presenting a tutorial featuring pyGNMI, a powerful tool for diagnosing network issues. During my talk, I used pyGNMI to visualize EVPN Layer2 and Layer 3 domains, sorting them by switch or network instance. I also added a special feature that detects discrepancies in the settings between different switches using the same EVPN domain – a great way to catch typos in your BGP/VXLAN settings.


The script demonstrates how to use pyGNMI to retrieve BGP EVPN information from a list of routers. It then formats the data for easy viewing.
For real world use cases, you would likely wrap pyGNMI with Nornir and leverage Nornir's inventory and task management capabilities, like shown here.

For this demonstration, I leveraged containerlab and Nokia SR Linux to build a VXLAN-EVPN Fabric, replicating a typical configuration I often use in my Kubernetes labs. I incorporated eBGP for underlay communication, and the topology I utilized comprised two spines, two leaf switches, and a border leaf.

In this blog post we are going to dive into the details of the script, discovering how it works and what it is capable of. If you want to try it out yourself, you can find the source code in the pygnmi-srl-nanog88 repo

NANOG88: gNMI and ChatGPT To Troubleshoot EVPN Datacenter Fabrics


I am happy that during NANOG88 conference, I had the privilege of presenting a tutorial that I am now pleased to inform you is available for viewing by the wider audience on YouTube.

NANOG88 provided a remarkable platform for knowledge exchange and collaboration among esteemed professionals in the field of networking and Internet operations. I was fortunate to have the opportunity to contribute to this extraordinary event by delivering this tutorial.

Are you interested in learning about EVPN-VXLAN technologies for Datacenters and creating a virtual network lab using containerlab? Then check this tutorial where we will guide you through the process.

We will cover everything from installing the necessary requirements for Python scripting using libraries like pyGNMI, a powerful tool used for operating and troubleshooting network elements with access via gRPC, and with the help of ChatGPT. We will show how to configure many network elements at once using Go Templates and gNMIc. By the end of the tutorial, you will have tips and tricks to perform various network automation tasks in your network datacenter environment and troubleshoot any issues that arise.

This tutorial is suitable for both experienced network engineers and beginners who want to enhance their knowledge of network design and operation with tools like GNMI, python and ChatGPT. The Information is available at Repo

Don't miss out on this opportunity to improve your network engineering abilities and take your skills to the next level.

Participants: Mauricio (Mau) Rojas