[adamcstephens]

Puppet has been doing this for over 15 years. Declarative config management is great and I love it. Unfortunately, it doesn't solve all administration problems as some software assumes an imperative installation or upgrade process.

[exdsq]

What’s an example of something you couldn’t upgrade declaratively, by having those imperative steps in a script?

[zhengyi13]

An awful lot of 3rd party "enterprise" systems have ancient, GUI installers. Particularly ones on Windows, although there are also occasional examples of this kind of silliness on Linux.

One timecard system we ran deployed a WAR in JBoss, but the associated DB schema upgrades were hand-compiled into a Java GUI with literally no externally-scriptable control surface.