[systemd-devel] [PATCH 17/17] networkd: add dhcp server support

[Eelco Dolstra]

Hi,

On 27/05/14 13:50, Lennart Poettering wrote:

>> On Mon, May 26, 2014 at 09:39:46PM +0200, Tom Gundersen wrote:
>>> When enabled in [Network] it will set up a dhcp server on the interface, listening
>>> on one of its statically configured IPv4 addresses and with a fixed size pool of
>>> leases determined from it.
>> Hi Tom,
>> before looking at the code, a couple of general questions:
>> - does the DHCP server have to be part of networkd? Isn't the job
>>   of acquiring addresses and giving out addresses separate and
>>   shouldn't
>>   two different processes be responsible?
> 
> I am very sure this should be in networkd. 
[snip]

That sounds reasonable. However, to be honest, I've never really understood why
networkd needs to be part of systemd in the first place. It seems to me that it
would work just as well as a separate package with its own releases. To me as a
downstream that would be preferable, since such a package can be upgraded
(mostly) independently from systemd. For instance, in NixOS we can upgrade
dhcpcd or wpa_supplicant pretty much in isolation from the rest of the system;
but getting the latest networkd would require getting the latest systemd, which
is typically a much bigger step since it potentially impacts much more of the
system.

You often point out (correctly) that systemd is not monolithic as it consists of
dozens of separate programs. But it *is* a monolithic package: those dozens of
programs can only be upgraded as a set.

> Remember that the goal here is not to write another ldap enabled
> monstrosity. 

A package becomes a monstrosity one "small" feature at a time. (And one person's
bloat is another person's essential feature.) For instance, networkd currently
lacks a WPA supplicant, which you surely need in a modern system. So should
systemd accrete a WPA supplicant? How about Bluetooth support? Etc. etc. I mean,
is there any concrete criterion about what should or shouldn't go into systemd?

-- 
Eelco Dolstra | LogicBlox, Inc. | http://nixos.org/~eelco/