Configuration to monitor Kubernetes Pods

Hi - I have just downloaded Telegraf and configured it to monitor the kubernetes Pods by enabling the following in the configuration file.

# Read metrics from the kubernetes kubelet api


## URL for the kubelet

url = “http://localhost:10255

It seems to throw up the following error

Jun 4 13:50:15 k8master kubelet: E0604 13:50:15.318929 474 summary.go:102] Failed to get system container stats for “/system.slice/docker.service”: failed to get cgroup stats for “/system.slice/docker.service”: failed to get container info for “/system.slice/docker.service”: unknown container “/system.slice/docker.service”

I have seen the troubleshooting guide from both K8 site and it looks ok. The Cgroup from Docker and the kubelet are both matching. But is anything else required to be changed in telegraf.conf?