That's why adding your user account to the docker group is a separate step that explicitly does not happen as part of the installation: https://docs.docker.com/engine/install/linux-postinstall/

> Warning

> The docker group grants root-level privileges to the user. For details on how this impacts security in your system, see Docker Daemon Attack Surface.

That's true, the majority of people probably install software without much thinking; but it's also true that it's always better to have at least some high level understanding how the specific piece of software works. What access the given software has, will it send something over the network or work locally; that kind of stuff.

As for Docker, I would assume everyone who ever tried to bind-mount a volume for writing from inside the container (on Linux*) then were surprised to see root-owned files in their bind-mounted directory. For me personally, that was the moment I realized that containers, by default, have root access to the filesystem. No written warning serves better than the need to chown some root-owned files.

* Not on macOS. On macOS Docker basically runs in a VM, and there's no root access to the host filesystem from what I understand.

[edit: formatting]

Most people buy scissors just to cut some paper. We can't expect everyone to recognize that they are sharp.

  > Most of us install Docker just to run a project locally

I'll admit, systemd is a bit more annoying, but the main annoyance is that there aren't the pre-built images that you can just set and go. That same capability exists with systemd (via `importctl` and `machined`), but those configurations don't already exist. But on the plus side, I've been working with systemd since pre-LLM days and I feel that they are pretty good at dealing with these configurations[0]. Now, with that out of the way...

Systemd already is working with your OS. So you get nice things like virtual machines (`systemd-vmspawn`), containers (`systemd-nspawn`), and portables[1] (`systemd-portabled`) (not to mention `homed`!). I've found these to be fairly easy to setup and quite natural if you're already used to the linux ecosystem. I've never been great at docker, but these have felt much more natural to me. So different strokes for different folks. There's definitely a learning curve, but that's also true for docker or any other container system. Importantly, I find security easier to handle with systemd because I can use `systemd-analyze` and the control settings are almost identical across VMs, spawns, and portables. So makes for less learning and greater control.

Definitely not for everybody, but I think is also a tool that's underappreciated.

[0] And I don't feel this way about bash scripting! The advantage here is that these systemd configuration files are fairly boilerplate. Enough that I stash templates in my dotfiles and copy paste them when I build new services, timers, machines, whatever. So perfect type of LLM task. 90% of the time. But hey, we're also on HN and I'm talking to the nerds. Systemd isn't for everyone

[1] https://systemd.io/PORTABLE_SERVICES/ also see https://github.com/systemd/portable-walkthrough Portables are actually often what people want with what they're doing with docker.

EDIT: I very frequently will spawn a machine to run a program that's on a different base distro. Not because I can't run/don't know how to run debs or rpms on arch based distros (I do), but because frankly, it is often easier to just spawn a container after I've already made the first image (cloning images is trivial).

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Given how few people read documentation, that's still pretty amazing

Podman on Windows - never been able to fully get rid of it and it throws errors on boot after uninstall. Was a fan, am now not.

This. I am running Claude in its own QEMU VM, it has git access to my project only if I explicitly unlock the ssh key for it. The other day I realized it trying to push a change, it didn't have permission, so it went looking for "workarounds" and found I had a github cli session and tried to use that, luckily the creds for that was also read scoped. But the point is, if I did not give permission and it sees I did not give permission, it should not try to find a workaround/exploit autonomously.

I don't really know of any distro that doesn't do that. All of Docker Inc. default installs and all of distros I know of don't automatically add you to the docker group. docker.com instructions has the infamous "linux post-install instructions" that explain and walk you though it.

The tragedy is of course that when security and usability collide, 80/20 rule will apply where 80% of people will pick usability over security. I have worked with many with the title >= "Senior Engineers" who saw that page, read the explanation, and still had no idea what the ramifications of their changes were. "Yeah sure it said any user in the docker group will be able to get root on the host, but aren't containers isolated?"

No, docker access means root. You can use "rootless" mode, in this case it means root in a user namespace (that is not the "host" user namespace).

That's not relevant. If you have access to the Docker daemon running as root, whether it's over a Unix socket or a TCP socket, you effectively have root.