Configuration Templating Could Be a Huge Win

The network automation evangelists love to tell you that automation is more than just device configuration management. They’re absolutely right… but it’s nonetheless amazing how much good you could do with simple tools solving simple problems.

Here’s what I got from Nicky Davey:

I’m working on a solution that will automate a DMVPN rollout to 350 sites, presenting to our worldwide operational teams how easy it is to roll out new sites with Ansible, and how quickly you can get Ansible up and running.

So far we have deployed 6 sites manually, and there are already inconsistencies between individual configurations. This isn’t surprising as our deployment document is 42 pages long. My automation solution should easily reduce it to under 10 pages.

We are migrating from an existing WAN network to DSL with DMVPN. As the new site router uses some parameters from the existing site router such as BGP ASN and network statement, I used Ansible to grab that config, extract some parameters, and use them to configure the new router via configuration template and host variables. Fantastic tool ;)

Lessons learned:

  • Consistency is one of the major automation wins.
  • Never underestimate the power of simple tools.

Want to develop something similar? You’ll find all the details you need in my Ansible for Networking Engineers webinar which includes a case study very similar to this one.

This blog post was initially sent to the subscribers of my SDN and Network Automation mailing list. Subscribe here.


  1. In my opinion your Ansible for Networking Engineers webinar is a little bit outdated regarding Ansible. When will you update it?
  2. Hello my Anonymous friend ;) You probably know I prefer facts over opinions, so it would be nice to get a list a few things you feel are missing. I'm aware of one or two (like XML parsing in 2.5), would love to see what you find most interesting.

    I also have to wonder why you're hiding yourself behind an opinionated anonymous comment. People with access to the material usually send me a direct email with actionable feedback.
Add comment