Comment by rcv | Hacker News Reader

Comment by rcv | Hacker News Reader

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> I genuinely don't understand what docker brings to the table. I mean, I get the value prop. But it's really not that hard to set up http on vanilla Ubuntu (or God forbid, OpenBSD) and not really have issues.

Sounds great if you're only running a single web server or whatever. My team builds a fairly complex system that's comprised of ~45 unique services. Those services are managed by different teams with slightly different language/library/etc needs and preferences. Before we containerized everything it was a nightmare keeping everything in sync and making sure different teams didn't step on each others dependencies. Some languages have good tooling to help here (e.g. Python virtual environments) but it's not so great if two services require a different version of Boost.

With Docker, each team is just responsible for making sure their own containers build and run. Use whatever you need to get your job done. Our containers get built in CI, so there is basically a zero percent chance I'll come in in the morning and not be able to run the latest head of develop because someone else's dev machine is slightly different from mine. And if it runs on my machine, I have very good confidence it will run on production.

OK, this seems like an absolutely valid use case. Big enterprise microservice architecture, I get it. If you have islands of dev teams, and a dedicated CI/CD dev ops team, then this makes more sense.

But this puts you in a league with some pretty advanced deployment tools, like high level K8, Ansible, cloud orchestration work, and nobody thinks those tools are really that appropriate for the majority of devteams.

People are out here using docker for like... make install.

Having a reproducible dev environment is great when everyone’s laptop is different and may be running different OSes, libraries, runtimes, etc.

Also docker has the network effect. If there was a good light weight tool that was better enough people would absolutely use it.

But it doesn’t exist.

In an ideal world it wouldn’t exist, but we don’t live there.

> Having a reproducible dev environment is great when everyone’s laptop is different and may be running different OSes, libraries, runtimes, etc.

Docker and other containerization solved the “it works on my machine” issue

almost. there is still an issue with selinux. i just had that case. because the client develops with selinux turned off, the docker containers don't run on my machine if i have selinux turned on.

you miss an intermediate environment (staging, pre-prod, canary, whatever you want to call it) with selinux turned on.

i don't. the customer does. and they don't seem to care. turning selinux off works for them and they are not paying me to fix that or work around it.

Docker is that lightweight tool, isn’t it? It doesn’t seem that complex to me. Unfamiliar to those who haven’t used it, but not intrinsic complexity.

15 years ago i has a customer who ran a dozen different services on one machine, php, python, and others. a single dev team. upgrading was a nightmare. you upgraded one service, it broke another. we hadn't yet heard about docker, and used proxmox. but the principle is the same. this is definitely not just big enterprise.

That is wild. I have been maintaining servers with many services and upgrading never broke anything, funnily enough: on Arch Linux. All the systems where an upgrade broke something were Ubuntu-based ones. So perhaps the issue was not so much about the services themselves, but the underlying Linux distribution and its presumably shitty package manager? I do not know the specifics so I cannot say, but in my case it was always the issue. Since then I do not touch any distribution that is not pacman-based, in fact, I use Arch Linux exclusively, with OpenBSD here and there.

i used "broken" generously. it basically means that for example for multiple php based services, we had to upgrade them all at once, which lead to a large downtime until everything was up and running again. services in containers meant that we could deal with them one at a time and dramatically reduce the downtime and complexity of the upgrade process.

Oh, I see what you mean now, okay, that makes sense.

I would use containers too, in such cases.

Would there still have been a problem if you were able to install multiple php versions side-by-side? HPC systems also have to manage multiple combinations of toolchains and environments and they typically use Modules[1] for that.

[1] https://hpc-wiki.info/hpc/Modules

probably not, but it wasn't just php, and also one of the goals was the ability to scale up. and so having each service in its own container meant that we could move them to different machines and add more machines as needed.

Imagine you have a team of devs, some using macOS, some using Debian, some using NixOS, some on Windows + WSL. Go ahead and try to make sure that everyone's development environment by simply running "git pull" and "make dev"

Ha, I've written a lot of these Makefiles and the "make dev" command even became a personal standard that I added to each project. I don't know if I read about that, or if it just developed into that because it just makes sense. In the last few years, these commands very often started a docker container, though. I do tend to work on Windows with WSL and I most of my colleagues use macOS or Linux, so that's definitely one of the reasons why docker is just easier there.

> so there is basically a zero percent chance I'll come in in the morning and not be able to run the latest head of develop because someone else's dev machine is slightly different from mine.

It seems you never had to deal with timezone-dependent tests.

What are timezone-dependent tests? Sounds like a bummer

I once had to work with a legacy Java codebase and they hardcoded the assumption their software would run in the America/New_York timezone, except some parts of the codebase and tests used the _system_ timezone, so they would fail if run in a machine with a different timezone.

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