Network interfaces not created in Docker container

[Francisco Javier Ros Muñoz]

Hi everyone,

I want a Docker container to be attached to multiple networks. After trying several options, the different NICs are never created within the container: 'ifconfig -a' just returns the loopback and (NATed) eth0 interfaces. I'm stuck with this, any hint would be more than welcome.

Vagrantfile: https://gist.github.com/anonymous/97785e28b1e0489c5b95

Output of 'vagrant up --provider=docker --debug': https://gist.github.com/anonymous/c2acd88a4dfd7e777f21

Thanks in advance,

fran

[Alvaro Miranda Aguilera]

if this a feature that came as part of Docker 1.0? attach to host nic?

can you check the docker version of the host/vm you are using?

Thanks

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[Francisco Javier Ros Muñoz]

Hi Álvaro,

Thanks for your input. I'm using Docker version 0.9.1, build 3600720.

From your comment, should I infer that Vagrant networking doesn't work with the docker provider?

Maybe I misunderstood something, but I was expecting Vagrant to set up multiple NICs (eth1, eth2, ...) within the docker container when I declare different 'vm.network' in the Vagrantfile.

Best,

fran

[Alvaro Miranda Aguilera]

Hello,

When I use docker to create a docker container, what I usually get is a port exposed to the host. and using vagrant you use 'ports' to map this information.

Say you create a docker container, with port 80 mapped to the host in 80..

http://host:80 will display the web server from the docker.

Why you require eth0/eth1/ethN ?

Long explanation/thinking below:......

the docker container will have access to internet, etc by the host, but you only get ports mapped between host-container or container-container.

NOTE: since docker 1.0 there is a new option to map docker container to a nic in the host, but I haven't used yet.

I haven't seen that docker use eth0 eth1 ethx as it's a container and not a full OS.

as part of docker 1.0 a new option came out that allow you map a docker conainer to the host nic.

outside vagrant, manually have you managed to create eth0 eth1 ethn inside a docker container in the way you want?

Vagrant will automate what you can do manually, but not sure if docker is what you require.

If you want to have eth0, eth1, etc, I will suggest give a try to vagrant-lxc plugin and have a look there, but my first suggestion will be test manually first, docker/lxc and then use vagrant to automate what you require.

[Francisco Javier Ros Muñoz]

Thanks a lot for your comments.

I need multiple interfaces within each docker container because I want to closely match a production environment where different subnetworks are used. For this, Vagrant's 'private_network' and 'public_network' are a perfect fit for my needs (at least in case they work along with Docker).
The new feature in Docker 1.0 you refer to isn't what I'm looking for, but thanks for the info.

Outside Vagrant, you can manually configure a container with multiple NICs. E.g. take a look to pipework.

So, I'm starting to think that 'private_network' and 'public_network' don't work at the moment when Vagrant deploys Docker containers. Otherwise, there's something wrong in my config and I'm missing something. I'd like to stick with Docker, but will try vagrant-lxc if I can't find any workaround.

Best,

fran

[Alvaro Miranda Aguilera]

Vagrant will automate what you do manually.

IF you can do those nic setup with docker (I assume with the new 1.0 map to nic you could, you need to test), then with vagrant you can automate.

If you create a linux box without docker, those network setup will work for sure.

Alvaro.