There are many different ways to configure networking on Linux. Debian and Alpine use ifupdown1, and Cumulus Networks invented ifupdown2; other distributions have various other systems, such as systemd-networkd and NetworkManager. This talk will present ifupdown-ng, a new project by the Network Services Association intended as a drop-in replacement for ifupdown1 and ifupdown2 installations. Presently, Alpine and Debian are the primary supported environments. Support for other Linux distributions and BSD is planned. With its modular design, ifupdown-ng intends to allow flexibility for today's modern networking setups, while being easy to extend. ifupdown-ng is Open Source and can be found on GitHub at: https://github.com/ifupdown-ng/ifupdown-ng/

1. Contemporary network con guration for Linux
ifupdown-ng
Aaron A. Glenn, Maximilian Wilhelm
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2. Agenda
1. Who's who
2. Why something new?
3. What we built
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3. Who's who Aaron A. Glenn
Network Janitor & Internetworking Curmudgeon
Ask me about Re-programmable Networks
Managing Director, Predicted Paths BV & Network Service Associates
Contact
@networkservice / @aag@bsd.network
aag@bgp.beer
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4. Who's who Maximilian Wilhelm
Senior Landscape Architect
OpenSource Hacker
Fanboy of
(Debian) Linux
IPv6
Occupation:
By day: Senior Infrastructure Architect, Uni Paderborn
By night: Infrastructure Archmage, Freifunk Hochstift
In between: Freelance Solution Architect for hire
Member of technical advisory board - Network Services Association
Contact
@BarbarossaTM
max@sdn.clinic
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5. Who's who
Why?
Field Experience Leads to Strong Opinions
NSP customer has uncommon financial and logistical constraints
3300 site opportunity
Initial 45 sites are intentionally in "most difficult" (network) environment
Two vendors and six months have not led to any definition of success
Given:
MIPS64 devices
Ancient Linux kernel
Need:
Linux 5.4+
handle complex configuration scenarios
avoid dependency on Python/golang/Rust/etc.
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6. Who's who
Why?
Strong Opinions Lead to New Code
New Opportunities
Alpine Linux project looking to modernize network configuration
'Complex' configurations are quite common!
Q: "where else might this be useful?"
New Thoughts
Disaggregated networking = Linux
"what if..."
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7. Who's who
Why?
Network Services Linux
Linux distribution for networking devices
Based on Alpine Linux
MUSL, no glibc
Flexible contemporary network configuration required
Came with ifupdown1
Not state of the art
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8. Who's who
Why?
Status quo - what's out there
iproute2
ifupdown
ifupdown1
ifupdown2
netplan
NetworkManager
systemd-networkd
RedHat universe
etc.
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9. Who's who
Why?
Status quo - ifupdown universe
Two mostly compatible suites
ifupdown1
Used in Debian (plus derivates) for decades
Used in Alpine for years (as part of busybox)
Written in C
Monolithic
Can be extended through /etc/network/if-X.d
ifupdown2
Used in Cumulus Linux
Available for Debian (plus derivates)
Written in Python
Modular, easy to extend
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10. Who's who
Why?
What we wanted
Compatible with ifupdown1/2
Support for contemporary features
Easy to extend
Small footprint
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11. Who's who
Why?
What we built
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12. Who's who
Why?
ifupdown-ng
Vision
Intended as a drop-in replacement for ifupdown1 and ifupdown2 installations
Today:
Alpine and Debian primary supported environments
Feature parity with ifupdown1
Dependency resolution
Extensible through executors
Meaningful documentation
Included in Alpine 3.13 and NSL 1
Planned:
Support for other Linux distributions and *BSD
Checking and reloading network configuration
Native executors using netlink
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13. Who's who
Why?
ifupdown-ng
Architecture
Core:
Written in C
Config parser
Compatibility layer
Dependency resolution
Executors:
Written in whatever you like (up to now: shell)
create, set up, tear down links, tunnels, ...
configure IPs
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14. Who's who
Why?
ifupdown-ng
Features
As of today:
static addresses (incl. pointopoint)
B.A.T.M.A.N. adv.
bonding / LAGs
(vlan-aware) bridges
DHCP
ethtool
dummy
PPP
tunnels (GRE, GRETAP, IP*, ...)
vEth
VRFs
VXLAN
Wireguard
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15. Who's who
Why?
ifupdown-ng
Outlook
Features:
Checking running config against configuration on disk
Reloading network configuration (with minimum impact)
Phase-wise execution
Native executors (C, netlink)
Support for static routes + PBR rules on interfaces
Support:
Automated integration tests
Become a native Debian package
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16. Who's who
Why?
ifupdown-ng
Visions
Managing WIFI interfaces
iface wlan0
wpa-ssid TwistedAir
wpa-psk muchsecure
ifmond daemon
Listens to netlink events
Network device added/removed
Cable plugged in or unplugged
Reacts to netlink events by (de)configuring interfaces as appropriate
Like udev, but for networking
-> Event-driven network management without blocking init
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17. Who's who
Why?
ifupdown-ng
Links
Code: https://github.com/ifupdown-ng/ifupdown-ng/
Discussion: #ifupdown-ng at irc.as7007.net
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18. Who's who
Why?
ifupdown-ng
Questions Questions?
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