[systemd-devel] Support `systemd-run --machine M --user` for running unprivileged

[Vito Caputo]

Subject basically says it all.  What's preventing us from supporting
this?

I'd personally appreciate being able to wire things up in my window
manager where I can run things via hotkeys like:

`systemd-run --machine finance --user firefox`
`systemd-run --machine entertainment --user firefox`

etc.

These containers are already configured using systemd-nspawn, with the X
socket bind-mounted.

I'm not using user namespaces, so this is just trying to run things as
the same uid inside the container as outside the container without root
or polkit kludges.

I can do this already using ssh and ssh keys, but it seems completely
unnecessary - systemd is already running everywhere, and I can use the
logind set-linger option to get the user instance up @ container boot.

Has anyone taken a look at what the technical barriers are?  I can't be
the only person wanting this kind of functionality.

Thanks,
Vito Caputo