Why podman command doesn't require a daemon?

[abitrolly]

Why all external commands need to run podman system service to interact with podman daemon while podman itself doesn't need it?

[baude]

I am not sure what you mean by external commands, but if you want to interact with Podman at an API level (specifically REST), then something has to "serve" that. The podman cli interacts directly with our libpod APIs in golang.

[abitrolly]

By external commands I mean this specific Go lib anchore/stereoscope#87

[rhatdan]

Basically external tools can either execute Podman command directly, which is difficult to manage, or they can use the API to a socket activated Podman which is more stable interface.

[abitrolly]

That still doesn't answer the question. By executing podman directly you mean executing podman binary? But the question is now podman binary operates on containers without bringing up daemon?

[rhatdan]

When my book comes out you will understand.

Podman just pulls an image creates storage, configures the OCI Runtime Specification and launches the OCI runtime (crun, runc, kata ...)
When you run a daemon like Docker or Podman as a socket activation, they
pull an image creates storage, configures the OCI Runtime Specification and launches the OCI runtime (crun, runc, kata ...)

There is nothing special about a daemon. Podman takes advantage of User Namespace to do all of this stuff in rootless mode.

The big difference between Docker is that the Docker Daemon controls multiple clients from interacting with container storage. While Podman uses the OS (file system locking) to allow multiple Podmans use the storage at the same time.