Dockernet

Dockernet enables you to build a flexible Docker network.

With Dockernet, you can add custom interfaces, configure static IP addresses, and adding static routes to a Linux container in a simple way.

Developer: Rayson Zhu vfreex@gmail.com

This project is inspired from pipework.

Content Table

• Things to note
• Add an extra interface
• Set a static IP address
• Add a static route

Things to note

1. Use the --net=none option when start a container to tell Docker not to configure its network automatically, leaving you free to build your custom network. For example, start a CentOS container without configuring the network:

$ sudo docker run -ti --rm --name=test_container --net=none centos:latest /bin/bash

2. If you want to start a process after extra network interface is up in a container, you can add dockernet script to your Docker image and call dockernet --wait <interface>, like dockernet --wait eth0. It will wait until that interface is present and in UP operational state.

Add an extra interface

Use dockernet <container> addif <interface> [<bridge>=docker0] to add an extra interface to a container.

Following command will add interface eth1 to container test_container and bridge this interface with docker0:

sudo dockernet test_container addif eth1

If you want to bridge your newly created interface to another interface br0, just issue:

sudo dockernet test_container addif eth1 br0

Then, set operational state to UP:

sudo dockernet test_container up eth1

Set a static IP address

Usually, you may want to clear all IP addresses associated with that interface:

dockernet <container> clearip <interface>

Then, add an IP address. You should specify an IP address in CIDR notation. <default gateway> is optional. If not specified, no default route will be configured.

dockernet <container> addip <interface> <CIDR> [<default gateway>]

For instance, we add IPv4 address 192.0.2.100/24 and IPv6 address 2001:db8:1234:5678::100/64 with default gateways 192.0.2.1 and 2001:db8:1234:5678::1 to interface eth1 for container test_container:

sudo dockernet test_container clearip eth1
sudo dockernet test_container addip eth1 192.0.2.100/24 192.0.2.1
sudo dockernet test_container addip eth1 2001:db8:1234:5678::100/64 2001:db8:1234:5678::1

Add a static route

You can use following notation to add or delete a route. The <ROUTE> part given in these commands are directly passed to the ip route command:

dockernet <CONTAINER> addroute <CONTAINER_IFNAME> <ROUTE>
dockernet <CONTAINER> delroute <CONTAINER_IFNAME> <ROUTE>

For instence, let's add 2 static routes to container test_container:

sudo dockernet test_container addroute eth1 203.0.113.0/24 via 192.0.2.254 metric 1000
sudo dockernet test_container addroute eth1 2001:db8:abcd::/48 via 2001:db8:1234:5678::ffff metric 1000

These two rules will tell your container that route packets targeting network 203.0.113.0/24 to router 192.0.2.254 and 2001:db8:abcd::/48 to router 2001:db8:1234:5678::ffff through interface eth1.