I agree with you, your declarative abstraction has to have an imperative implementation underneath that will do all the dirty work. Ansible presents this declar

I agree with you, your declarative abstraction has to have an imperative implementation underneath that will do all the dirty work. Ansible presents this declarative interface at the module level (if the module is implemented properly, most aren't), and a playbook is an imperative list of declarations to be applied. Roles also combine a list of imperative steps into a declarative interface. Since apparently (I try to avoid ansible, so I might be missing something) playbooks are the go-to approach of using ansible this means that most uses of ansible are imperative (in the context of configuring a system), unless you only ever give a system a singular role and then you are probably defining your role in imperative steps. A system like NixOS on the other hand presents the entirety of a system configuration in a single declarative interface that is applied in one go, while applying such a configuration to a system can be a thought of as an imperative step (although it is usually a singular, unconditional step). So it is declarative at a higher abstraction level.