This document introduces DOCKNET, a Golang package for advanced Linux networking configuration. It aims to provide functionality that Docker lacks for configuring interfaces like VLANs and MAC VLANs. The package fixes issues with existing Golang Netlink implementations and allows configuration of container networks beyond what Docker supports currently. It is still in development but aims to be released within a couple weeks. The presentation includes a live demo and discusses using DOCKNET to add interfaces to Docker containers.

1. DOCKNET - golang package for Linux networking
DevOps Exchange London, #DOXLON
26th June, 2014

2. About me…
• Ex-Rackspace, couple of startups in and outside of UK
• Currently freelancing
• Twitter: @milosgajdos
• Linkedin: http://uk.linkedin.com/in/milosgajdos
• Professional (technology) ranter or better - Ops guy
• Programming language tourist currently loving Go

3. How and why docknet
• Started as a personal interest in Linux container networking
(http://containerops.org/2013/11/19/lxc-networking/)
• Docker does not offer advanced networking functionality
available in LXC/OpenVZ
• No properly functional Go library which would allow you to
configure Linux networking programatically without shelling
out

4. Application delivery DOCKERIZE ALL THE THINGS!

5. Infrastructure delivery
• Network is an essential part of IT infrastructure
• Well designed network offers better scalability, security,
easier management etc.
• Legacy network setups and various esoteric or financial
requirements leave us deal with ….

6. Insane network infrastructures o_O

7. Netlink & RTNetlink
• Netlink is a datagram-oriented messaging system in
Linux for user-space applications to communicate with
Linux kernel
• mostly used by networking tools (iproute2), but there is
some use of it in other non-networking kernel
subsystems
• RtNetlink is a library used for configuring and managing
networking devices, routing, neighbouring etc.

8. Go netlink
• Found 2 Go implementations:
1. github.com/abneptis/GoNetlink
• does not seem to be actively developed any more - last
commit about 4 years ago
• couldn’t compile it with latest Go compiler
2. github.com/docker/libcontainer/ (netlink package)
• used by Docker o/
• more idiomatic, still work in progress
• seems broken - NEEDS FIXING

9. Fixing netlink package

10. docknet
• general network managing and configuration library for Linux OS -
not just containers!
• uses properly functioning netlink package which offers more
functionality than libcontainer’s one (VLANs, MAC VLANs etc.)
• no syscalls in netlink package any more - syscalls are NOT netlink !
• allows for advanced networking configuration of your containers (not
necessarily Docker based): VLANs, MAC VLANs, multiple network
interfaces etc.
• Still WORK IN PROGRESS… still private, should be released in a
week or two

11. docknet sneak peek
• Add an extra veth interface into Docker from the host
machine:
https://gist.github.com/milosgajdos83/7cc9028a962fb5635ada
• Add a MAC VLAN interfaces into Docker from the host
machine:
https://gist.github.com/milosgajdos83/296fb90d076f259a5b0a

12. TIME FOR LIVE DEMO!

13. I AM HIRING ……

14. Links
• http://www.linuxjournal.com/article/8498
• http://man7.org/linux/man-pages/man7/netlink.7.html
• http://man7.org/linux/man-pages/man3/netlink.3.html
• https://github.com/torvalds/linux/blob/master/net/core/rtnetlink.c
• https://github.com/torvalds/linux/blob/master/include/linux/
rtnetlink.h
• https://github.com/docker/libcontainer/blob/master/netlink/
netlink_linux.go