Summary
In this chapter, you learned how to install and set up Batfish, initialize a snapshot with the configurations that were generated in Chapter 4 for the Arista data center topology, and extract the facts that Batfish was aware of from its offline analysis. Finally, you interacted with Batfish custom assertions to make sure your configuration was valid and free of references to unknown configuration elements, you made sure the single ACL named “loopback” didn’t have statements that could never be evaluated, and lastly, you learned how to use Batfish offline analysis to validate BGP neighbor compatibility and even that BGP sessions were properly established.
Offline network validation is a powerful tool, allowing an automation engineer to feel confident in network changes before ever touching the live network configurations. There are a few other tools to consider in this space. PyATS is a Cisco project that has multi-vendor support as well as an Ansible...
