Exposing Tap interface from docker container to docker host

Question

my application creates a tap interface inside a docker container. e.g. tap_1: ip: 192.168.2.1

My requirement is that any packet coming on docker host can be directly sent to tap interface which is present inside the docker container. I am basically try to avoid one hop of sending first to docker0 and then forward it to specific tap interface.

I tried going through pipeworks and bridge network, but seems none of them can resolve my requirment.

Appreciate your help. Thanks Ankit

Answer 1

You need to set capabilities for the Container you are starting. By default the docker containers cant do everything they want, unless you assign them capabilities.

With capabilities you are pretty much map the network device to the container and then do whatever you want. Not sure if this is the optimal way but it will get you started.

Moreover, the container networking works little differently depending upon which layer are you using.

Example:

docker run --cap-add=NET_ADMIN --device /dev/net/tun:/dev/net/tun -i -t alpine /bin/ash