windows-subsystem-for-linuxdocker-desktopcni

Location CNI plugin configuration(s) of the Docker Desktop with WSL2 network infrastructure?

Investigating Docker Desktop on Windows with WSL2 using the Edgeshark open source tool, I get the following network topology for the container workload:

Deocker Desktop with WSL2 network topology

Please note how this is a Docker-in-containerd setup, so the Docker engine lives inside a containerd container, in the services.linuxkit namespace of containerd.

Now I "suspect" that Docker Desktop might use CNI plugins with containerd to network its managed containers, such as the docker1-eth0 and services1 -eth0 VETH "networks". If this actually is the case, where can I find the CNI plugin configuration for this setup?

Solution

  • As it turns out, we need a way to look into the environment around the Docker engine, and a way to see it, is to deploy an inspection container as follows:

    docker run -it --rm --privileged --pid host alpine

    Next, we can look around via the wormhole of /proc/1/root/; this turns up a directory /proc/1/root/containers with an onboot sub-directory. There's more here:

    004-docker-net/runtime.json contains a "section" about (network) interfaces:

        "interfaces": [
        {
            "name": "docker0",
            "add": "veth",
            "peer": "docker1",
            "createInRoot": false
        }
    ],

    So, there is no "traditional" CNI plugin configuration used here, but Docker Desktop does its own thing.