the worlds gone mad

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.

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.

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.

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.

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…..

Link-state advertisements (LSA) are used to communicates the router’s local routing topology to all other local routers in the same OSPF area. There are 11 types of LSAs although only the 6 most commonly used ones are described in this post.

I am currently studying to rectify my CCIE and it is at these times that I realise there is so much I have studied and learnt but forgotten. There are many cool things I come across that I think at the time are useful features that I need to remember, but unfortunately if you don’t have a real world use for them they are soon put to the back of the brain and over time forgotten. The same applies with taking for granted the way things work, be that ARP, DHCP or the process a switch or router goes through when moving traffic. I came across some of my old notes on CEF which I thought worth sharing.