Docker. It’s been around longer, it’s more polished, easier to learn, simpler to use, supported everywhere and by everything, easy to find solutions when you search for help, doesn’t depend on systemd, compatible with every container image out there, and you can do things with it even if it’s not the “correct” way to do it while podman will tell you “no, you can’t do that”.
If your distro offers it, rootless podman + podman system service is the best setup, IMO. That will give you a docker command that is 1-to-1 compatible with docker and lets you use tools like docker-compose that expect a docker service socket. Then you can just follow tutorials that only explain things for docker.
What is rootless bring brought up so much? It’s a container, it’s isolated from the host anyway, what does it matter what user runs inside? And if something breaks into the container they can trash the app in it and the shared volumes anyway, even if they’re not root.
Defense in depth. If something escapes the container it’s limited to only what’s under that user and not the whole system. Having access to the whole system makes it easier for malware to hide/persist itself.
Correct me if I’m wrong but containerization is enforced by the kernel, correct? If something escapes you’re pretty much screwed anyway.
Because a container is only as isolated from the host as you want it to be.
Suppose you run a container and mount the entire filesystem into it. If that container is running as root, it can then read and write anything it likes (including password databases and /etc/sudo)
So what? If I mount / in the container and choose to run it as root that’s my business. Why would the containerization engine second-guess what I’m doing?
How would you like it if sudo told you “I can’t let you be root, you could read and write anything you like, including password databases and /etc/sudo”?
It depends on the use case. The most common security issue I have seen with docker is on Linux desktop systems: docker deamon runs as root and user wants to use it to test all kinds of containers. So they make the docker socket accessible to the user, to lazy to use “sudo docker” every time… Having access to the docker socket means having the same permissions as the one running the daemon: root . Your browser effectively now has root permissions. At this point you could just login as root to your desktop.
There’s real usability benefits too. I’ve collected some anecdotes from Reddit:
Rootless podman is my first choice for using containers now, it works fantastically well in my experience. It’s so much nicer to have all my container related stuff like volumes, configs, the control socket, etc. in my home directory and standard user paths vs. scattered all over the system. Permission issues with bind mounts just totally disappear when you go rootless. It’s so much easier and better than the root privileged daemon.
and,
If you are on Linux, there is the fantastic podman option “–userns keep-id” which will make sure the uid inside+the container is the same as your current user uid.+
and,
Yeah in my experience with rootless you don’t need to worry about UID shenanigans anymore. Containers can do stuff as root (from their perspective at least) all they want but any files you bind mount into the container are still just owned/modified by your user account on the host system (not a root user bleeding through from the container).
finally,
The permissions (rwx) don’t change, but the uid/gid is mapped. E.g. uid 0 is the running user outside the container, by uid 1 will be mapped to 100000 (configurable), and say 5000 inside the container is mapped to 105000. I don’t remember the exact mapping but it works roughly like that.
Podman, rootless containers work well, and there is no central process running everything. I like that starting containers on boot is integrated with systemd.
How do you automatically start podman containers? I currently just manually add systemd entries but that’s a lot more cumbersome than Docker which doesn’t require you to do anything at all.
I use Quadlet, which is now merged in podman. The only issue I had with it is running system systemd services as other (rootless) users, I can’t get it to create cid files that the users can access. In those cases only, I have to modify the generated services files, which defeats the purpose.
Since I use Docker Compose with Podman, I just make a single systemd service to run Docker Compose on boot, thereby starting all my containers at once.
That’s an interesting way to do it. Do you have everything in 1 compose file?
i would like to try… but as far as i know, there is no “docker compose up -d”
Don’t overthink this. Just start using something.
Podman, dockerd is a single point of failure
