Kubelet Rootfs.UsedBytes missing in /stats/summary in Minikube

Question

We are consuming kubelet /stats/summary endpoint.

We noticed that the metrics returned are not always present and might be missing in some scenarios.

In particular we are interested in Rootfs.UsedBytes that in missing in minikube but present in other environments.

Command to retrieve /stats/summary from kubelet, notice that the port can vary in different k8s flavours

token=$(k get secrets <service-account-token-with-enough-privileges> -o json \
| jq .data.token -r | base64 -d -)

k run curler --rm -i --restart=Never --image nginx -- \
curl -X GET https://<nodeIP>:10250/stats/summary --header "Authorization: Bearer $token" --insecure

"pods": [
{
...
   "containers": [
   {
   ...
      "rootfs": {
         ...
         "usedBytes": 36864,
         ...
       }

• Why is that?
• Is there a similar metric more reliable?
• Can add anything in Minikube to enable that?

EDIT:

It is possible that the issue is related to --driver=docker option of minikube

Answer 1

To clarify I am posing community wiki answer.

The problem here was resolved by changing driver to Hyperkit.

According to the documentation:

HyperKit is an open-source hypervisor for macOS hypervisor, optimized for lightweight virtual machines and container deployment.

There are two ways to install HyperKit (if you have installed Docker for Desktop, you don't need to do anything - you already have HyperKit):

• you can install HyperKit from GitHub
• if you have Brew Package Manager - run the following command:

brew install hyperkit

See also this reference.