How does it work in practice with things like Rapsberry Pi/Banana Pi etc.?

Question

Do it yourself

I'm interested in them as a server. Therefore, this question:
Is a monitor with a keyboard required for them? Or is there, as on firmware for routers (such as OpenWrt), the SSH / Web interface is immediately raised and can be configured via the network?

Answer 1

Not required.
Connect the power to the raspberry, connect it with a network wire to the router and you can safely knock on ssh.

Answer 2

On many (if not all) axes, ssh is already running for such stray, so most likely it is not necessary. but if there is no dhcp on the network, then you will have to configure the network with a monitor and a keyboard.