Earlier this month I mentioned on Mastodon that I was replacing a Docker-based local development environment at my day job with a Nix-based one, orchestrated with overmind and a justfile. There was quite a lot of interest in particular in how overmind and just could be used to replace a container / compose-based local development. While I can’t share the details of the significantly more complex migration I did at my day job (yet!

Some folks on the internet were interested in how I had managed to ditch Docker for local development. This is a slightly overdue write up on how I typically do things now with Nix, Overmind and Just.

  • Jeezy@lemmy.worldOPEnglish
    0·
    1 year ago

    Hi!

    First I’d like to clarify that I’m not “anti-container/Docker”. 😅

    There is a lot of discussion on this article (with my comments!) going on over at Tildes. I don’t wanna copy-paste everything from there, but I’ll share the first main response I gave to someone who had very similar feedback to kick-start some discussion on those points here as well:

    Some high level points on the “why”:

    • Reproducibility: Docker builds are not reproducible, and especially in a company with more than a handful of developers, it’s nice not to have to worry about a docker build command in the on-boarding docs failing inexplicably (from the POV of the regular joe developer) from one day to the next

    • Cost: Docker licenses for most companies now cost $9/user/month (minimum of 5 seats required) - this is very steep for something that doesn’t guarantee reproducibility and has poor performance to boot (see below)

    • Performance: Docker performance on macOS (and Windows), especially storage mount performance remains poor; this is even more acutely felt when working with languages like Node where the dependencies are file-count heavy. Sure, you could just issue everyone Linux laptops, but these days hiring is hard enough without shooting yourself in the foot by not providing a recent MBP to new devs by default

    I think it’s also worth drawing a line between containers as a local development tool and containers as a deployment artifact, as the above points don’t really apply to the latter.

    • Hexarei@programming.devEnglish
      1·
      1 year ago

      If your dev documentation includes your devs running docker build, you’re doing docker wrong.

      The whole point is that you can build a working container image and then ship it to a registry (including private registries) so that your other developers/users/etc don’t have to build them and can just run the existing image.

      Then for development, you simply use a bind mount to ensure your local copy of the code is available in the container instead of the copy the container was built with.

      That doesn’t solve the performance issues on Windows and Mac, but it does prevent the “my environment is broke” issues that docker is designed to solve

    • CodeBlooded@programming.devEnglish
      1·
      1 year ago

      Docker builds are not reproducible

      What makes you say that?

      My team relies on Docker because it is reproducible…

      • uthredii@programming.devEnglish
        0·
        1 year ago

        You might be interested in this article that compares nix and docker. It explains why docker builds are not considered reproducible:

        For example, a Dockerfile will run something like apt-get-update as one of the first steps. Resources are accessible over the network at build time, and these resources can change between docker build commands. There is no notion of immutability when it comes to source.

        and why nix builds are reproducible a lot of the time:

        Builds can be fully reproducible. Resources are only available over the network if a checksum is provided to identify what the resource is. All of a package’s build time dependencies can be captured through a Nix expression, so the same steps and inputs (down to libc, gcc, etc.) can be repeated.

        Containerization has other advantages though (security) and you can actually use nix’s reproducible builds in combination with (docker) containers.

        • nickwitha_k (he/him)@lemmy.sdf.orgEnglish
          1·
          1 year ago

          That seems like an argument for maintaining a frozen repo of packages, not against containers. You can only have a truly fully-reproducible build environment if you setup your toolchain to keep copies of every piece of external software so that you can do hermetic builds.

          I think this is a misguided way to workaround proper toolchain setup. Nix is pretty cool though.

    • Ethan@programming.devEnglish
      0·
      1 year ago

      Cost: Docker licenses for most companies now cost $9/user/month

      Are you talking about Docker Desktop and/or Docker Hub? Because plain old docker is free and open source, unless I missed something bug. Personally I’ve never had much use for Docker Desktop and I use GitLab so I have no reason to use Docker Hub.

      • Jeezy@lemmy.worldOPEnglish
        0·
        1 year ago

        I believe this is the Docker Desktop license pricing.

        On an individual scale and even some smaller startup scales, things are a little bit different (you qualify for the free tier, everyone you work with is able to debug off-the-beaten-path Docker errors, knowledge about fixes is quick and easy to disseminate, etc.), but the context of this article and the thread on Mastodon that spawned it was a “unicorn” company with an engineering org comprised of hundreds of developers.

        • Ethan@programming.devEnglish
          0·
          1 year ago

          My point is that Docker Desktop is entirely optional. On Linux you can run Docker Engine natively, on Windows you can run it in WSL, and on macOS you can run it in a VM with Docker Engine, or via something like hyperkit and minikube. And Docker Engine (and the CLI) is FOSS.

          • Jeezy@lemmy.worldOPEnglish
            0·
            1 year ago

            I understood your point, and while there are situations where it can be optional, in a context and scale of hundreds of developers, who mostly don’t have any real docker knowledge, and who work almost exclusively on macOS, let alone enough to set up and maintain alternatives to Docker Desktop, the only practical option becomes to pay the licensing fees to enable the path of least resistance.

            • Martin@feddit.nuEnglish
              0·
              1 year ago

              We are over 1000 developers and use docker ce just fine. We use a self hosted repository for our images. IT is configuring new computers to use this internal docker repository by default. So new employees don’t even have to know about it to do their first docker build.

              We all use Linux on our workstations and laptops. That might make it easier.

              • Von_Broheim@programming.devEnglish
                0·
                1 year ago

                Op comes off a bit, uninformed. E.g. I use docker engine and docker compose inside WSL2 on windows and performance is fine, then I use Intellij to manage images/containers, the service tab handles the basics. If I need to do anything very involved I use the cli.

                Docker is fine, the docker desktop panic really only revealed who never took the time to learn how to use docker and what the alternative UIs are.