[Samba] Samba embedded device?

[George]

Hi team!

At work I have several small branch offices with ~5 PCs each. All PCs are
member of a Samba4 domain, whose DCs are on the headquarters (linked by
consumer grade VPNs)

I want to ship "some small, cheap, reliable and magical device" to each
branch, in order to provide just 2 things:
* AD replication
* File shares

That't it, period. Nothing fancy.

Suggestions??? What do you use for this purpose??

Thanks a lot.

George