A short description of container namespaces, Linux virtual Ethernet interfaces and how to use them in Docker and Open vSwitch to create a self-contained network with hundreds of nodes on a single host machine.

1. Goran Cetušić
1
Building a network
emulator with Docker and
Open vSwitch

2. Goran Cetušić
2
What do we need?
● Resource isolation
● A PC
● A link
● A switch
● A router

3. Goran Cetušić
3
Namespaces

4. Goran Cetušić
4
Veth interfaces
● Network pipes
– One pipe
– Two net interfaces
● Packet flow:
– Packet enters one
end/interface
– Packet exits other
end/interface

5. Goran Cetušić
5
Docker

6. Goran Cetušić
6
FROM debian:jessie
MAINTAINER Goran Cetusic <goran.cetusic@gmail.com>
ENV HOME=/root VTYSH_PAGER=more TERM=vt100 PAGER=less
ADD . /build
RUN /build/prepare.sh &&
/build/system_services.sh &&
/build/utilities.sh &&
/build/cleanup.sh
CMD ["/usr/bin/iinit.sh"]
Dockerfile

7. Goran Cetušić
7
OpenvSwitch

8. Goran Cetušić
8
Networking

9. Goran Cetušić
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Architecture

10. Goran Cetušić
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Init process

11. Goran Cetušić
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The zombie problem

12. Goran Cetušić
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Optimization

13. Goran Cetušić
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Docker storage drivers
// Slice of drivers that should be used in an order
priority = []string{
"aufs",
"btrfs",
"devicemapper",
"vfs",
"overlayfs",
}

14. Goran Cetušić
14
Tying it together
sudo docker run -d --privileged --net='none' gcetusic/vroot
sudo docker inspect -f "{{.State.Pid}}" fa41ef950da2
6748
sudo ip link add name hostif type veth peer name guestif
sudo ln -s "/proc/6748/ns/net" "/var/run/netns/6748"
sudo ip link set guestif netns 6748

15. Goran Cetušić
15
Resources
● https://github.com/imunes/imunes
● https://github.com/imunes/vroot-linux
● https://hub.docker.com/r/imunes/vroot

16. Goran Cetušić
16
Questions?