Use Kubernetes-nodes Metrics to determine kubelet cert expiry

[Kevin Cameron]

Hi There,

  I have several older kubernetes clusters and I need a way to alert on the kubelet/kubeadm certs before they expire.

From the kubernetes-nodes job we get several metrics:

apiserver_client_certificate_expiration_seconds_count

apiserver_client_certificate_expiration_seconds_sum

apiserver_client_certificate_expiration_seconds_bucket

But I am not really clear on how to use these values to determine either a countdown to expiry or the actual expiration date.  The bucket metrics have an "le" label but not sure what that means.

Thanks,

Kevin