Podman is a daemonless container runtime for Linux compatible with Docker.
It offers several advantages over using Docker to manage and run containers.
First, there is no overhead associated with running a background service as is the case with Docker.
Podman also allows users to run rootless containers which provides a higher degree of protection for the system.
Podman integrates deeply with Linux, taking advantage of a number of specific features.
Notably, it uses namespaces for process isolation and integrates nicely with systemd.
Just like Kubernetes, Podman is built on the concept of pods, groups of one or more containers, instead of individual containers.
Podman is only available in the Ubuntu repositories as of Ubuntu 20.10, making it just an apt install away.
For older Ubuntu LTS releases, the Kubic PPA can be used to get Podman which is described here.