[systemd-devel] systemd-networkd questions

[Dan Williams]

On Tue, 2013-11-12 at 23:19 +0100, Tom Gundersen wrote:
> Hi Dan,
> 
> On Tue, Nov 12, 2013 at 10:38 PM, Dan Williams <dcbw at redhat.com> wrote:
> > 1) what is lacking in other userspace solutions (NetworkManager,
> > ConnMan, wicked, initscripts, etc) that requires
> > yet-another-network-daemon?
> 
> Without criticizing any of the existing solutions, some of the things

To be honest, it would be helpful for you to raise your concerns at
least with NetworkManager, since many of the concerns that we've heard
about running in smaller and enterprise environments have recently been
addressed, or are longstanding misconceptions of things NM did in the
past but has not done for years.

> that motivated my interest in this is that I think we need: something
> easily configured via plain configuration files by a sysadmin,

NM uses .ini-style files in /etc for all configuration these days, and
also has plugins for reading distro-specific configuration files if the
user wants those.

> something that would take a limited amount of space (including its
> dependencies) so it could be reasonably used in an initrd, something

What are your space constraints in terms of both disk space and RSS
usage?

> which would be fast/efficient, so not e.g. calling out to external
> tools/daemons for stuff like dhcp/ipv4ll.

What are your requirements for being "fast/efficient"?  How long do you
require a DHCP exchange to take, on average?  How long do you require
IPv4LL addressing to take, on average?  How much worse than these
requirements are existing solutions?

> Essentially, I see us taking over from what initscripts (and similar
> solutions in various distributions) are currently doing, and
> peacefully coexisting with connman and networkmanager for the
> foreseeable future. Hopefully we'll manage to cooperate on overlapping
> functionality, but I think it is a bit early in the game to start
> discussing that yet.
> 
> > 2) do you expect that systemd-networkd will grow to include bridge,
> > bond, and team setup?  how about other "enterprise"/"server" interface
> > types like macvlan/vtap, tun/tap, gre, vxlan, ovs, etc?  All these are
> > enterprise things that typically won't change during a specific bootup,
> > but which static "servers" increasingly use.  If you don't expect these
> > to be supported, why not?
> 
> Most of these things we expect to support eventually. We'll have to
> discuss on a case-by-case precisely which ones.

At some point, when doing "most of these things", systemd-networkd
becomes another first-tier network management daemon like the 6 or 8
that already exist.  Is that the intention?  Is it useful to have two
different services that both do the same thing?

Dan

> > 3) Is there expected to be D-Bus interfaces for controlling or
> > monitoring the network interfaces and configuration data?  If not, why
> > not?
> 
> This is expected, yes. At first we will at least expose the state of
> the networks/links, and later also allow them to be configured. All
> this would be via dbus.