find_veth_docker

Simple script to find out which veth interface on the host corresponds to the eth0 interface of a container

Requirements

After using this script in countless environments, I had to come to the conclusion that the containers in question have to have iproute2 utility installed. The scripts uses the command ip in the containers to gather the necessary information. If your container does not have it, install it. Don't forget that most containers are optimized for size, i.e., before installing a package you have to update the repository. In case of Debian/Ubuntu-based container images, do the following.

sudo docker exec -it <CONTAINER_NAME> apt-get update
sudo docker exec -it <CONTAINER_NAME> apt-get install iproute2

For Redhat/etc-based containers, please adopt the above-mentioned commands.

Usage

This script finds out which vethXXXX is connected to what container!
Example: sudo ./find_veth_docker.sh -n <CONTAINER_NAME> -i <INTEFACE_IN_CONTAINER>
		-n <CONTAINER_NAME>: set here the name of the container (Default: No name specified, printing all containers' data).
		-i <INTERFACE_IN_CONTAINER>: set here the name of the interace in the container (Default: eth0).

Example

sudo ./find_veth_docker.sh -n google
VETH@HOST	CONTAINER
veth003b9c4	google

Using output for scripts

You might want to change some setting for a particular container's vethXXXX device. Let's take an example for ethtool that disables checksumming on the interfaces.

sudo ethtool -K $(./find_veth_docker.sh -n google |grep -v @|awk '{print $1}') tx off rx off