the worlds gone mad

we've lost the hope we had

Posted on 9 October 2021   13 min read

Nornir: Tasks, Plugins and Templates

building and running tasks

Nornir tasks are run against all or a subset of inventory members with the result formatted into a framework structured to show what was run against whom and the results. Tasks can be custom built python code or pre-built plugins that have been installed and imported.


Posted on 3 October 2021   10 min read

Nornir: Inventory Structure and Filtering

updating and filtering the inventory

The inventory is at the core of Nornir holding all the hosts that tasks will be run against and the variables that will be used by those tasks. Before any tasks can be run by Nornir the inventory has to be initialised.


Posted on 28 September 2021   12 min read

Nornir - The Basics

general nornir information to get started

If you have an understanding of Python and have been working with Ansible it is likely at some point you will get to the stage where you ask yourself ‘there has to be something better’. For network automation that better could well be Nornir.


Posted on 27 July 2021   11 min read

Virtual Tunnel Interface (VTI) VPN

vti ipsec vpn between asa and asr

Over the years I have built numerous IPsec VPNs on ASAs using crypto maps and an ACL for the interesting traffic. For a simple solution to join small sites with no need for routing these work great and keep the complexity down to a minimum. For more complex environments or cloud connectivity you are probably going to need to use VTIs, this post goes through the process of building VTI VPNs between an ASR and ASA.


Posted on 6 June 2021   5 min read

EVE-NG Cloud NAT

dynamically nat lab devices behind the eve primary ip

This post explains how to configure EVE-NG as a DHCP server (isc-dhcp-server) assigning IPs to lab devices that are then dynamically NATed behind the primary EVE management IP address (iptables masquerade) to provide Internet breakout.


Posted on 27 May 2021   6 min read

The Evolution of Labbing

how the worlds changed

A trip down memory lane on how things have changed in labbing from using prehistoric switches bought on eBay through emulators that took longer to configure than the labs to the present day solutions that can programmatically build a multi-vendor lab in minutes. Kids today don’t know they are born…..


Posted on 23 March 2021   14 min read

Automate Leaf and Spine Deployment - Part6

post validation

The 6th post in the ‘Automate Leaf and Spine Deployment’ series goes through the validation of the fabric once deployment has been completed. A desired state validation file is built from the contents of the variable files and compared against the devices actual state to determine whether the fabric and all the services that run on top of it comply.




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