Re: using nix in place of ansible/chef/puppet/salt etc.
One of things that makes it far superior to these solutions, is that while many of them try to be declarative it still an iterative hack to emulate it.
For example if you use your CM to install a package on the system, or create a file in /etc. If you remove that statement the file or package will still be there.
In NixOS it will be as if it was never there. The reason for it is that the existing CM work by modifying current OS, while NixOS rebuilds the entire OS every time you make a change (thanks to cacheing that operation doesn't take as long as it would normally do).
As for using things in production, I generally like things that are well established. So it took many years before I got the courage to propose it, but frankly I don't think it ever let me down. As I used it always act predictable, both the NixOS as well as build (as long as you pin down nixpkgs).
The only thing to worry about is if the outside environment demands a change you better know how to do it. For example application works fine, suddenly you have higher traffic and things are crapping out and maybe you need to change some settings or there was a bug in one of your dependency and a new version isn't in nixpkgs. You better know how to do those things.
One of things that makes it far superior to these solutions, is that while many of them try to be declarative it still an iterative hack to emulate it.
For example if you use your CM to install a package on the system, or create a file in /etc. If you remove that statement the file or package will still be there.
In NixOS it will be as if it was never there. The reason for it is that the existing CM work by modifying current OS, while NixOS rebuilds the entire OS every time you make a change (thanks to cacheing that operation doesn't take as long as it would normally do).
As for using things in production, I generally like things that are well established. So it took many years before I got the courage to propose it, but frankly I don't think it ever let me down. As I used it always act predictable, both the NixOS as well as build (as long as you pin down nixpkgs).
The only thing to worry about is if the outside environment demands a change you better know how to do it. For example application works fine, suddenly you have higher traffic and things are crapping out and maybe you need to change some settings or there was a bug in one of your dependency and a new version isn't in nixpkgs. You better know how to do those things.