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"Same execution environment everywhere" is one way which developers use Docker. Docker gets this by copying the layers of a built image. Unlike nix, the image b

"Same execution environment everywhere" is one way which developers use Docker. Docker gets this by copying the layers of a built image. Unlike nix, the image building itself doesn't need to be reproducible. So you can have a Dockerfile which works now but will fail to build in however many months. "Reproducible builds" do get you "same execution environment everywhere". But they have the stronger guarantee that for the same inputs, outputs will be the same. IMO/IME, I don't think that aspect of nix is a strong selling point for use of nix on developer workstations. Probably thanks to less-elegant solutions like "<language> Version Manager" etc.. But I think the nix language makes for a nicer way of describing a package of software you're developing in terms of dependencies and outputs than Dockerfile.

tomberek 6y ago
I do have to commend Docker for providing and managing an agreed upon VM for non-Linux users to host all their containers. It's the "killer-feature" that has made it as successful as it is. But underneath it requires a VM (libcontainer,LXC,virtualbox,hyperkit,etc) on non-Linux machines. This helps developers work together and quickly get small projects up and running. I'd contend that after a while, a mess of containers/sidecars ends up becoming just as difficult to manage as a mess of native binaries. Hence the growth of so many container management systems. Now, because they are re-inventions of service managers we get the benefit of designing them from scratch for modern needs, but also loose many of the benefits of well understood semantics of native processes. Looking for feedback: I've been playing with an idea (and have a system in production using it to try out the concept) where the Dockerfile only contains busybox+nix and you when you run it you specify an environment as a Nix path. Specify a binary cache via env vars. Using "nix run" this will download all deps and run your program, with bind mounts all containers can share the host cache. Put a RUN into the Dockerfile and you can prefetch all the deps. Basically it's a Docker container that uses Nix at build or run time for all the heavy lifting, instead of the docker layers mechanism.
- wwright 6y ago
  Have you checked out the official container system in NixOS?
  - tomberek 6y ago
    Yes, but it requires NixOS. This “docker compatibility layer” is about being able to use nix style packaging in environments that expect Docker. Eg: ECS. https://github.com/tomberek/nix-runner https://github.com/tomberek/nix-runner
- solarkraft 6y ago
  How much overlap is there between your idea and Nixery?

tomberek 6y ago

I do have to commend Docker for providing and managing an agreed upon VM for non-Linux users to host all their containers. It's the "killer-feature" that has made it as successful as it is. But underneath it requires a VM (libcontainer,LXC,virtualbox,hyperkit,etc) on non-Linux machines. This helps developers work together and quickly get small projects up and running. I'd contend that after a while, a mess of containers/sidecars ends up becoming just as difficult to manage as a mess of native binaries. Hence the growth of so many container management systems. Now, because they are re-inventions of service managers we get the benefit of designing them from scratch for modern needs, but also loose many of the benefits of well understood semantics of native processes. Looking for feedback: I've been playing with an idea (and have a system in production using it to try out the concept) where the Dockerfile only contains busybox+nix and you when you run it you specify an environment as a Nix path. Specify a binary cache via env vars. Using "nix run" this will download all deps and run your program, with bind mounts all containers can share the host cache. Put a RUN into the Dockerfile and you can prefetch all the deps. Basically it's a Docker container that uses Nix at build or run time for all the heavy lifting, instead of the docker layers mechanism.

wwright 6y ago
Have you checked out the official container system in NixOS?
- tomberek 6y ago
  Yes, but it requires NixOS. This “docker compatibility layer” is about being able to use nix style packaging in environments that expect Docker. Eg: ECS. https://github.com/tomberek/nix-runner https://github.com/tomberek/nix-runner
solarkraft 6y ago
How much overlap is there between your idea and Nixery?