Docker networking was introduced in Docker 1.9.0 and has continued to be improved upon and expanded. Key features introduced include support for multiple micro-segmented networks, built-in multihost networking using VXLAN, pluggable network plugins, and integration with Docker Swarm and Docker Compose. Later versions added additional capabilities like service discovery using embedded DNS, network load balancing, and experimental Macvlan and IPVlan drivers to connect containers to specific VLANs. Docker networking allows containers to be connected to different network types including default bridge networks, user-defined bridge networks, and overlay networks spanning multiple Docker hosts.

1. Docker Networking

2. Docker 1.9.0
• New top-level UX & API : docker network
• Support for multiple micro-segmented networks
• Built-in multihost networking using VXLAN based overlay driver
• Support for third party network plugins
• Ability to dynamically connect containers to multiple networks
• Pluggable and user-defined IP address mgmt
• Integration with Docker Swarm

3. Docker 1.10.0
• Service Discovery using embedded DNS
• IP stability using `--ip / --ipv6` option
• Network-scoped Alias support
• `—link` support in user-defined networks
• Network isolation using `--internal` option
• Multi-host networking in all supported kernels (3.10+)
• Integration with Docker Compose

4. Docker 1.11.0
• Built-in load-balancing using DNS-RR
• Service Discovery for IPv6 (AAAA Records)
• Experimental Macvlan & IPVlan drivers

5. Docker Networking
use-cases

6. Use-case1
Default Bridge Network
(docker0)

7. eth0 eth0 eth0
docker0 docker0 docker0
C1
eth0 eth0
C2
eth0
C3 C1
eth0 eth0
C2
eth0
C3 C1
eth0 eth0
C2
eth0
C3
ToR switch / Hypervisor switch / …
iptables :
NAT / port-mapping
iptables :
NAT / port-mapping
iptables :
NAT / port-mapping

8. Use-case2
User-Defined Bridge Network

9. Host1 :
$ docker network create -d bridge -o com.docker.network.bridge.name=brnet brnet
$ docker run --net=brnet -it busybox ifconfig
eth0
brnet
172.18.0.1
ToR switch / Hypervisor switch / …
eth0
C1
Host1
eth0
C2
eth0
C3
iptables :
NAT / port-mapping
eth0
brnet
172.18.0.1
eth0
C4
Host2
eth0
C5
eth0
C6
iptables :
NAT / port-mapping
eth0
brnet
172.18.0.1
eth0
C7
Host3
eth0
C8
eth0
C9
iptables :
NAT / port-mapping
Host2 :
$ docker network create -d bridge -o com.docker.network.bridge.name=brnet brnet
$ docker run --net=brnet -it busybox ifconfig
Host3 :
$ docker network create -d bridge -o com.docker.network.bridge.name=brnet brnet
$ docker run --net=brnet -it busybox ifconfig

10. Use-case 3
Docker Overlay Network

11. eth0
C1
eth1 eth1
C2
eth1
C3
ToR switch / Hypervisor switch / …
docker0docker_gw
eth0
C1
eth1 eth1
C2
eth1
C3
docker0docker_gw
eth0
C1
eth1 eth1
C2
eth1
C3
docker0docker_gw
ov-net1 ov-net1 ov-net1
VXLAN-VNI 100 VXLAN-VNI 100
eth0 eth0 eth0 eth0 eth0 eth0 eth0 eth0 eth0
VXLAN-VNI 100
iptables :
NAT / port-mapping
iptables :
NAT / port-mapping
iptables :
NAT / port-mapping

12. Use-case 4
Plumbed to underlay vlan with built-in IPAM
Experimental vlan drivers (macvlan & ipvlan)
https://github.com/docker/docker/blob/master/experimental/vlan-networks.md

13. # vlan 10 (eth0.10)
$ docker network create -d macvlan —subnet=10.1.10.0/24
—gateway=10.1.10.1 -o parent=eth0.10 mcvlan10
$ docker run --net=mcvlan10 -it --rm alpine /bin/sh
# vlan 20 (eth0.20)
$ docker network create -d macvlan —subnet=10.1.20.0/24
—gateway=10.1.20.1 -o parent=eth0.20 mcvlan20
$ docker run --net=mcvlan20 -it --rm alpine /bin/sh
# vlan 30 (eth0.30)
$ docker network create -d macvlan —subnet=10.1.30.0/24
—gateway=10.1.30.1 -o parent=eth0.30 mcvlan30
$ docker run --net=mcvlan30 -it --rm alpine /bin/sh

14. User Guide
https://docs.docker.com/engine/userguide/networking/dockernetworks/
Docker overlay networking
https://docs.docker.com/engine/userguide/networking/get-started-overlay
http://container42.com/2015/10/30/docker-networking-reborn/
Experimental docker vlan drivers :
https://github.com/docker/docker/blob/master/experimental/vlan-
networks.md
Resources