I explained specifically using multiple comparisons why it's different from Ansible and Puppet. Several of the guarantees made by Nix were never promised by Puppet and Ansible, such as enforced idempotency and managing the distribution from the ground up. These are fundamental differences, and not a better screwdriver. If you've ever used Puppet and Ansible, you'd know that an OS upgrade will break your scripts. I've had Puppet and Ansible break out from under me countless times. That is basically close to impossible with Nix, because the OS is not under it, it IS the OS. It fully manages anything that it deploys. Puppet and Ansible often just use external tooling like package managers or edit existing config files, which is grossly error prone. Nix IS the package manager, and it IS the config file. This is a huge difference. I understand that you can install a package from scratch and deploy entire config files using Puppet and Ansible, but this is side-stepping the underlying OS's capabilities, and this sort of discipline can only be maintained by a single experienced engineer, and not a large group of people updating the config, unlike Nix, which enforces deployment.

To say that Nix is a better screw driver is like saying that you could write the same level quality and reliability of software using Bash as in Rust. Rust is just a better screw driver than bash - I suppose it's true in some technical legal sense, but most people won't agree, and it's not true in any sense that is useful or valuable.

Again, it's an explanation only a passive bystander.

They're declarative, idempotent, and intended to manage infrastructure, operating systems and clusters, and coordinate application delivery, key rotation and configuration. Repeatability, rollback, and version control are the basic design tenets.

Sorry to hear that an OS upgrade broke your scripts once, but that's hardly the fault of configuration management tools in general or the Puppet/Ansible/Chef/Salt family in particular.

As you might tell from between the lines, I have some experience with these tools in various environments. But I also see the need for another generation, mainly because of the large shift to Kubernetes application delivery. The insistence of these tools to manage the entire OS stack makes people regard them as too complex for what they need. It is my personal belief that the concept of a host is limiting the continued acceptance of this type of tools and I have been spare time experimenting with other primitives to describe state on, such as binary file archives.

Playing with Nix, it is my impression that it is quite similar to other configuration management tools, a host is still the basic entity we serialize state on. State transitions are a linear graph.

What people describe as problematic with configuration management in general is usually perceived complexity, and Nix seems to have the potential for more of that. But I have not used Nix in anger, or in any type of real world complex environment, and I would be very happy to learn from someone who has experience.

> They're declarative, idempotent, and intended to manage infrastructure, operating systems and clusters, and coordinate application delivery, key rotation and configuration. Repeatability, rollback, and version control are the basic design tenets

That's what I'm saying, they are not declarative or idempotent in my experience, at least not Ansible. I'm not as familiar with Puppet so I wont say anything too confidently with that, but Ansible is 1. not idempotent as it allows you with ease to execute operations that can modify the system differently based on the system's state, and 2. not declarative, as the operations are step-wise.

Anyway sounds like you have experience and an interest in the field. My experience with Nix is more personal than professional but I'm happy to try to answer any questions you have about it.