I use podman almost exclusively at this point. I like having the rootless containers and secrets management. If you're on Debian, though, I strongly suggest pulling podman from Trixie. The version in Bookworm is very out of date and there's been a lot of fixes since then.

Podman not because of security but because of quadlets (systemd integration). Makes setting up and managing container services a breeze.

Podman

• rootless by default
• daemonless
• integration with systemd, made even easier by podman-generate-systemd
• no third-party APT repository required, follows the same lifecycle as my LTS (Debian) distro
• podman and docker command-line are 100% compatible for my use cases

Can't help with much of this but I think I can resolve the last question for you, since I don't see anyone else trying.

How long is a piece of string?

Exactly twice as long as half of its length.

As long as you’re on Linux, podman is superior and will do all of the things you’re asking about. If you need to also support Windows or Mac, Docker is the only thing that will work (although people have told me Rancher isn’t bad now for a couple of years).

I haven't switched products but I did go through a process of hardening my containers to a degree. I did find that the hardening is limited by the authors of the software and if they have built their apps with security in mind.

I have always used docker-compose I found that easier to see what needed to be tweaked.

Some helpful links

https://docs.docker.com/docker-hub/vulnerability-scanning/

https://cheatsheetseries.owasp.org/cheatsheets/Docker_Security_Cheat_Sheet.html

I switched from Dockerd to K3s. First you get the benefits of the Kubernetes API but also Pod Security Context, Pod Security Admission and Network Policies which help to reduce attack surface while simplifying your setup. But if you do want to use Podman look into running your containers as read only, drop all capabilities and unprivileged.

I'm actually in the process of switching over from docker to podman. Its definitely a learning curve, ie. Setting up systems integration etc.

I do love it but its been a bit of a pain, for instance I'm still trying to figure out the errors I'm getting when trying to deploy my matrix and vikunja containers, I'm getting permission errors and can't find dB errors. I k ow little about podman right now but I would definitely recommend it since it is open source and runs rootless by deafult.

Definitely Podman

Alternatively you could use docker in virtual machines

I'm running podman and podman-compose with no problem. And I'm happy. At first I was confused by the uid and gid mapping the containers have, but you'll get used to it.

This are some notes I took, please don't take all of it for the right choice.

Podman-Stuff

https://github.com/containers/podman/blob/main/docs/tutorials/rootless_tutorial.md

storage.conf

To use the fuse-overlay driver, the storage must be configured:

.config/containers/storage.conf

[storage]
  driver = "overlay"
  runroot = "/run/user/1000"
  graphroot = "/home/<user>/.local/share/containers/storage"
  [storage.options]
    mount_program = "/usr/bin/fuse-overlayfs"

Lingering (running services without login / after logout)

https://github.com/containers/podman/issues/12001

https://unix.stackexchange.com/questions/462845/how-to-apply-lingering-immedeately#462867

sudo loginctl enable-linger <user>

I started with rootless podman when I set up All My Things, and I have never had an issue with either maintaining or running it. Most Docker instructions are transposable, except that podman doesn't assume everything lives as dockerhub and you always have to specify the host. I've run into a couple of edge cases where arguments are not 1:1 and I've had to dig to figure out what the argument is on podman. I don't know if I'm actually more secure, but I feel more secure, and I really like not having the docker service running as root in the background. All in all, I think my experience with rootless podman has been better than my experience with docker, but at this point, I've had far more experience with podman.

Podman-compose gives me indigestion, but docker-compose didn't exist or wasn't yet common back when I used docker; and by the time I was setting up a homelab, I'd already settled on podman. So I just don't use it most of the time, and wire things up by hand when necessary. Again, I don't know whether that's just me, or if podman-compose is more flaky than docker-compose. Podman-compose is certainly much younger and less battle-tested. So is podman but, as I said, I've been happy with it.

I really like running containers as separate users without that daemon - I can't even remember what about the daemon was causing me grief; I think it may have been the fact that it was always running and consuming resources, even when I wasn't running a container, which isn't a consideration for a homelab. However, I'd rather deeply know one tool than kind of know two that do the same thing, and since I run containers in several different situations, using podman everywhere allows me to exploit the intimacy I wouldn't have if I were using docker in some places and podman in others.

2¢

I switched and was very glad to do so. You increase your security and so far I haven't seen any downside. Every container I've tried has worked without issues, even complex ones.

I'm very much biased towards Podman, but from what I understand rootless Docker is a bit of an afterthought, while Podman has been developed from the ground up with rootless in mind. That should be reason enough.

The very few things Docker can do that Podman struggles a bit with are stuff that usually involves mounting the Docker socket in the container or other stupid things. Since you care about security, you wouldn't do that anyway. Not to mention there's also rootful Podman, when you need that level of access.

I'd recommend an RPM-based distro with Podman, the few times I've tried Podman on a deb distro, there's always been something wonky. It's been a while, though.

Hey bigdickdonkey, I recently tried and wasn’t able to shit my way through podman, there just wasn’t enough chatter and guides about it. I plan to revisit it when Debian 13 comes out, which will include podman quadlets. I also tried to get podman quadlets to work on Ubuntu 24 and got closer, but still didn’t manage and Ubuntu is squicky.

I read about true user rootless Docker and decided that was too finicky to keep up to date. It needs some annoying stuff to update, from what I could tell. I was planning on many users having their own containers, and that would have gotten annoying to manage. Maybe a single user would be an OK burden.

The podman people make a good argument for running podman as root and using userns to divvy out UIDs to achieve rootless https://www.redhat.com/en/blog/rootless-podman-user-namespace-modes but since podman is on the back burner till there’s more community and Debian 13, I applied that idea to Docker.

So I went with root Docker with the goals of:

• read only
• set user to different UID:GID for each container
• silo containers in individual Docker networks
• nothing gets /var/run/docker.sock
• cap_drop: all
• security-opt=no-new-privileges
• volumes all get tagged with :rw,noexec,nosuid,nodev,Z

Basically it’s the security best practices from this list https://cheatsheetseries.owasp.org/cheatsheets/Docker_Security_Cheat_Sheet.html

This still has risk of the Docker daemon being hacked from the container itself somehow, which podman eliminates, but it’s as close to the podman ideal I can get within my knowledge now.

Most things will run as rootless+read-only+cap_drop with minor messing. Automatic ripping machine would not, but that project is a wild ride of required permissions. Everything else has succumbed, but I’ve needed to sometimes have a “pre launch container” to do permission changes or make somewhere like /opt writable.

I would transition one app stack at a time to the best security practices, and it’s easier since you don’t need to change container managers. Hope this helps!

One of the main reason I switched to podman was its compatibility with firewalld. Haven't used rootless docker, but podman and podman-compose gets the job done for me.

Not sure if it makes a difference and not quite your question but I've just switched away from nextcloud-aio to just having my own docker compose, so I have better control and know what's going on more. I always found it funny and when installing on a new VPS decided to try. It was surprisingly straightforward and Ive been able to install everything I need.

Let me know if my docker compose would help. I still need to add the backup solution but it's going to be straightforward as well.