At my company, we run our CI/CD (Jenkins) using the Docker-in-Docker paradigm to facilitate easy maintainability of the CI itself and allow us to run containerized builds.

When we shifted to RHEL 8, we attempted to move this over to Podman and it went miserably (this was back in November 2019). The main reason being is that podman-in-podman doesn't work and had bugs (at least back in Nov 2019). Maybe it fixed now but this was our experience. We ended up doing quite a bit of analysis on podman only to conclude it's simply not there yet relative to docker (ecosystem and ergonomics).

There are quite a few corner cases that docker quite simply supports out of the box beautifully that podman doesn't support or just has bugs.

I like the what the project is trying to solve by being daemonless, but this is not as simple as a drop in replacement for docker that RedHat markets it as (alias docker=podman).

We ended up sticking to docker professionally and personally, I am still using docker over podman. The ecosystem and ergonomics are just far too nice to give up over podman.

quietbritishjim

> Docker-in-Docker paradigm

Apologies for the patronising comment, but do you really mean that? Docker in Docker works but is intended for the developers of Docker to debug Docker itself. Usually for running Docker from within a container, you just hook up the Docker client to the TCP port of the Docker daemon running outside the container, which isn't strictly Docker-in-Docker.

I ask this in case you're trying a wildly use case (if you really are running true Docker-in-Docker), or are making an unfair comparison (if you're just using the usual Docker client in container to daemon on host). In the latter case, I must admit I don't know what the idiomatic alternative would be for podman, given that I know nothing about it except that it's daemonless (and even that I only learned by reading your comment).

nhoughto

Docker in docker is a very common pattern in CI, in some cases is the only way to achieve certain tasks.

haberman

What kinds of tasks require two levels of containers?

nhoughto

“kind” is a example in my day to day, how do I run an ephemeral kube cluster in ci to deploy and test my app against without dind/kind? I want N clusters running on 1 host to support many CI jobs.

https://github.com/kubernetes-sigs/kind https://github.com/bsycorp/kind