Add support for Docker with containerd-snapshotters

[mkutlak]

There is an experimental feature in Docker for containerd snapshotters [1][2][3].

$ cat /etc/docker/daemon.json
{
  "features": {
    "containerd-snapshotter": true
  }
}

$ docker info | grep -iA1 "storage"
 Storage Driver: overlayfs
  driver-type: io.containerd.snapshotter.v1

When it is enabled, images are stored in /var/lib/containerd/io.containerd.snapshotter.v1.<storage_driver> instead of /var/lib/docker/image/<storage_driver> and it causes cAdvisor to keep failing with this error message:

manager.go:1116] Failed to create existing container: ... failed to identify the read-write layer ID for container "<CONTAINER_ID>". - open /rootfs/var/lib/docker/image/overlayfs/layerdb/mounts/<CONTAINER_ID>/mount-id: no such file or directory

Relevant line of code:

cadvisor/container/docker/handler.go

Line 107 in 255cff7

return "", fmt.Errorf("failed to identify the read-write layer ID for container %q. - %v", containerID, err)

This issue might be also relevant: moby/moby#46757

---

1. https://www.docker.com/blog/extending-docker-integration-with-containerd/
2. https://docs.docker.com/engine/storage/containerd/#enable-containerd-image-store-on-docker-engine
3. https://github.com/containerd/containerd/blob/main/docs/snapshotters/README.md#snapshotters