I've seen several post about installing docker to run an Empyrion dedicated server.

do I understand correctly, that docker is a or creates a container to run programs.
and that it is needed to run Empyrion as a dedicated server.
because the currently Empyrion is windows only ( or so all that I've seen indicates that that is the only version to date, (and maybe plans are in the works ))

also can I assume that a container is need for any non-Linux programs or is it more like create virtual machine to run programs in the own space.

is there little or a lot of overhead having docker installed?

I already have the two links need to Install docker and Empyrion but want to know a little more about docker first.
Empyrion - Galactic Survival > Guides > MadHammer's Guides
which has a like to installing docker on ubuntu
so, i should be all set there.