The case for declarative network automation: Some network teams are finding power and simplicity in the shift from telling devices what to do—imperative programming—to describing what they should be—declarative programming.

Abstract

[...]more than 40% roll their own automation solution using various forms of imperative scripting or programming (mostly Python), and about 50% engage a different model instead of or in addition: declarative automation. HTML can be considered a declarative language—“This web page should have this text in this size, and that image underneath, and two buttons here and here to take users to pages B and C.” So can SQL—“The data set should contain all the records that meet conditions A and B and C.” Declarative approaches to network automation take a lot of the burden of programming off network engineers. [...]with the usual tradeoff on trusting tools provided by vendors to handle imperative automation behind the scenes, declarative automation offers a powerful tool with which network teams can advance the cause of broader automation without having to devote themselves to becoming imperative-style procedural programmers.