Podman vs Docker on Ubuntu#

Key Facts#

• Ubuntu 25.04 (Plucky Puffin) is NOT officially supported by Docker Engine. Docker's official Ubuntu support covers only LTS releases: Ubuntu 24.04 (Noble), 22.04 (Jammy), and 26.04 (Resolute). 1
• Podman is available as a package in Ubuntu 25.04 (version 5.4.1+ds1-1 in Plucky), but it is not installed by default in a standard Ubuntu desktop or server install — it is an optional package that can be installed via apt. 2
• Ubuntu 24.04 (Noble) does not have a published Podman package. 3
• The course documentation at installation-locale.adoc incorrectly states: "Ubuntu 25.04+ est livré avec Podman par défaut" (Ubuntu 25.04+ ships with Podman by default). This claim is inaccurate in two respects: (1) Podman is not the default container engine on Ubuntu 25.04 out of the box; (2) Ubuntu 25.04 is a non-LTS interim release that is end-of-life and unsupported by Docker.

The Socket Conflict Issue#

When both Docker and Podman are installed on the same system, a socket conflict can arise:

• Podman creates /run/podman/podman.sock (or /run/user/$UID/podman/podman.sock for rootless mode)
• Docker expects /var/run/docker.sock
• If podman-docker (a compatibility shim) is also installed, it can create a /var/run/docker.sock alias pointing to the Podman socket, causing Cannot connect to the Docker daemon errors when Docker Engine is also present

Docker's own installation docs list podman-docker as a conflicting package that must be removed before installing Docker Engine. 1

Resolving the Conflict (as documented in the course)#

The course offers two options when Podman and Docker coexist (installation-locale.adoc lines 14–42):

Option 1 — Install Docker alongside Podman:

sudo apt install docker.io
sudo systemctl enable --now docker
sudo usermod -aG docker $USER

Option 2 — Remove Podman, then install Docker (recommended for the course):

sudo apt remove podman
sudo apt install docker.io
sudo systemctl enable --now docker
sudo usermod -aG docker $USER

A logout/login is required after usermod for group membership to take effect.

Ubuntu Version Support Matrix#

Sources: 1 2 3

What the Course Documentation Should Say#

The speaker notes in installation-locale.adoc lines 79–81 contain two factual errors:

1. Wrong codename: The notes call Ubuntu 25.04 "Noble Numbat" — but Noble Numbat is Ubuntu 24.04. Ubuntu 25.04 is Plucky Puffin.
2. Overstated claim: Podman is available as an apt package in Ubuntu 25.04 (Plucky), but it is not shipped as the default container engine in a standard install. A user would have to explicitly install it.

The practical socket conflict described in the course can occur if a user manually installs Podman alongside Docker on any Ubuntu release, but it is not an automatic consequence of running Ubuntu 25.04 and is not a platform-level default change.

The accurate statement would be: "Ubuntu 25.04 is an unsupported interim release for Docker Engine. If you have both Podman and Docker (or the podman-docker shim) installed, socket conflicts can occur. Use Ubuntu 22.04 or 24.04 LTS for best Docker Engine compatibility."

Avoiding the Issue Entirely#

GitHub Codespaces — the recommended course environment — ships Docker pre-configured and avoids any Podman/Docker conflict entirely. 4 5

Key References#

• Docker Engine Ubuntu installation requirements 1
• installation-locale.adoc — course slide with the inaccurate Podman-default claim
• github-codespaces.adoc — course slide recommending Codespaces to avoid local conflicts
• Podman in Ubuntu Plucky (25.04) on Launchpad 2