Using Podman

What is Podman?

Podman is a container management tool that is compliant with the Open Container Initiative spec.

Basic usage of Podman

Podmans basic usage emulates the Docker CLI:

podman run -dt -p 8080:80/tcp docker.io/library/httpd

Podman as a Docker replacement

The podman-docker package can setup Podman to emulate the Docker api and socket.

Podman desktop is a replacement for Docker desktop

SELinux & Podman

• SELinux is a kernel security module that implements for more in-depth access control mechanisms.

• SELinux adds adittional contexts to files / folders that can cause permission issues for containers.

  • To "just make it work" with podman, add :z to the end of volume mounts

Podman and systemd

• systemd can manage automatically starting and stopping containers using systemd unit files.

  • This can be a desireable way to manage starting different containers when specfic events happen, such as system power on, or another container starting.

• Quadlets are files that are used to generate systemd services from a Podman container.

  • The documentation for this is at docs.podman.io/en/latest/markdown/podman-systemd.unit.5.html

Quadlet example

~/.config/containers/systemd/sleep.container

[Unit]
# Description for the unit file
Description=The sleep container
# Dependencies before container can be ran
After=local-fs.target

[Container]
# Image
Image=registry.access.redhat.com/ubi9-minimal:latest
# Command
Exec=sleep 1000

[Install]
# Start by default on boot
WantedBy=multi-user.target default.target

Demo!