1: Actually, last time I looked at NixOS, you could also install things the imperative way, but that's a silly thing to do.
All these tools have to deal with the problem of state. Most of them choose to handle it implicitly...the state of the system is the state and the tool tries to determine it at runtime. This strategy has all the problems listed in the article. Other tools attempt to keep a record of the state. This solves the issues from the article but has it's own set of issues (mostly state management and state corruption). Neither approach is objectively right and both have their tradeoffs.
I honestly agree with the original, down-voted, poster...the article is a bit preachy without much insight. The rise of DevOps has turned system administration into a CS problem. And, like most other CS problems these days, it all boils down to managing state. And just like there are many approaches to state management in application architecture (RDBMS, NoSQL, Paxos/Raft, etc) where no solution is objectively right, there will be many approaches to state management in DevOps where no solution is objectively right. The author obviously has his preferences, but his analysis is biased and incomplete and should be called out as such.
It sounds like it's mostly a provisioning tool, and doesn't really help with configuration management once your machines exist. From the "terraform vs chef / puppet" page:
> Terraform enables any configuration management tool to be used to setup a resource once it has been created. Terraform focuses on the higher-level abstraction of the datacenter and associated services [...]
So it sounds like like a very nice provisioning tool, but doesn't really compete with NixOS itself. Perhaps you could even use it to provision NixOs machines?
I'm really not trying to sound like a shill for Hashicorp, but we use a bunch of their tools and find them to be, overall, very worthwhile and focused on accomplishing a single logical task which makes them easily composable with tools from other vendors. I also don't want it to sound like I'm criticizing Nix or NixOS...they sound like excellent tools. My only point was that there are other ways to solve the problems expressed in the posting and that each solution has tradeoffs that DevOps needs to consider when designing infrastructure. Your blog struck me as being a strawman criticism of somewhat dated tools without consideration for newer options, especially since your discussion of Docker was so narrowly focused on the actual Docker tool without any consideration given for Fleet, Swarm, ECS or any of the host of orchestration options in the Docker ecosystem.
If you'd written it more from a position of "here's how NixOS has made my life easier," you'd probably find that people would be more receptive to it. But, instead, it had a "here's why NixOS is better than the alternatives" feel to it which is going to rub people the wrong way when it's pretty clear that you're not aware of all the alternatives. NixOS is one good option, but it's by no means the only good option.
> Perhaps you could even use it [Terraform] to provision NixOs machines?
You definitely can, so long as your servers are virtualized. Terraform is significantly less useful in a bare-metal world. However Terraform is really about provisioning specific machines. For example, you might write Terraform to provision 1 SMTP server, 3 web front-ends behind a load balancer and 2 database hosts. But it's pretty crude at doing provision-time tasks...it basically allows you to run shell commands. Where you'd do the bulk of your provisioning would be in a tool like Packer, Aminator or other such tool that creates VM images that can be deployed. That's where you'd start with a base NixOs image and then declare what's installed on an SMTP server, a web front-end and a database server. Terraform would just reference those images and size the machines.
I definitely have humble requirements in terms of deployment size, so (for me) any orchestration tool is likely to be way more effort than it's worth. I compared NixOS (not a deployment tool) to those other (small-scale deployment and/or configuration management tools) because that's what I and plenty of developers I know have used, and I think the comparison helps illustrate the issues that NixOS can solve. Hopefully those who _do_ have experience and need for larger orchestration software can tell from reading whether the problems NixOS solves are relevant to them.
Actually not, because if you do, you will find these changes added to a file declaratively describing all the changes you have committed to the system (or user-context) as a whole.
It's a good way to build a config if you're not fully comfortable with nix-syntax.
I don't remember where the file ends up, but it is there.
My hunch is that it could scale well, but would require some integration work in order to use it nicely with existing orchestration tools. I don't know exactly what that would look like, or if it would be worth the effort of going off the beaten track.
And you're done. Server up and running. done about 20 of them in the last twelve months. What's all this "package" stuff about? what's wrong with yum?
The thing with package managers is that it get's boring to do everything all over again for a large amount of servers. Also your brain memory does not have a reliable version control. You need to keep why and how you do certain stuff on your server somewhere else. First thing that comes to your mind is a shell script and people are already using something better ( ansible, puppet, etc. ). Now, with this article, I see that there is something even better than this.
By using Puppet, I never have to read my colleagues custom setup script because store it there. By checking in everything to version control, I see who has done what by reading the changelog.
If you are only managing your own servers and keep a strict discipline you will see less of the benefits.
This article is fluff because of this lack of experience; it honestly reads as another "looks at this cool thing I know nothing about!"
Don't get me wrong, Nix sounds great, but this is a poor article from an inexperienced sysadmin who is unable to really point out the pros and cons.