Network Automation in 2026

So it’s 2026, nobody should be logging into all their devices and changing the configs manually anymore. Everyone is talking about CI/CD, Ansible, Python, Jinja2 etc and you don’t know where to start or what to learn. While I encourage everyone to learn at least the basics of software development, as that will help anyone in their careers, or at least help you do repetative work easier.

Intro

Nobody wants to login into multiple hundreds of devices to change configs. So we automate where we can. This article tries to give a little direction in your automation efforts.

Atomic replace

So you have probably looked at adding/deleting parts of your config, while this works, it’s very complicated and gives your co-workers the option to still change configs manually. It’s infinately easier to replace the entire config every time you run your automation. This ensures your “inteded” state in your Source of Truth is a reflection of your production network. Not all vendors have a good option to execute this, choose your equipment accordingly.

Workaround for manual additions

So, it’s 4 am your phone is ringing because everything is broken, you fix your configs manually on the CLI because it’s still a great tool and faster then reworking your automation to add the nerd-knob you just used to fix the problem. The problem this causes is that the following morning, your colleagues run the automation and your local-changes are gone, as they should be. So pretty please with sugar on top, give your admins a way to add some manual commands to your auto-generated configs. This has saved my behind on multiple occasions.

Source of Truth

I’m not going to debate which SoT is best, this is a discussion that is endless and you can find a lot of information about this elsewhere. But you do have to use something. I don’t care if its a tool like Netbox, Nautobot or Infrahub, or maybe a series of text-files in git, whatever works for your organisation is the best solution for your. It should however not be your network, please define what you want your network to look like somewhere, and use that information to generate configurations etc. for your network.

Input should be easy

If you use a SoT, it should be easier to enter the inteded state there, than manually changing configs on your devices. Otherwise no-one will use your SoT. I currently use Netbox as a SoT, and use the Custom Scripts feature to input into Netbox. So adding a leaf to a fabric is matter of running the script and defining which rack the leaf should be added to. The script then reserves ports, ips, etc. etc. Much easier than doing all this by hand.

Think smaller

I’ve spoken about generating configs, and pushing them to your devices, but there are many other uses for your automation. Think about using automated testing to validate your changes. Use your automation to grab information from your network to locate problems. IMHO it’s better to start with these types of things, as they will save you a lot of time, and gives people trust in your automation solution.