For Kubernetes: Verifying whether Metrics Server is running

As an optional step, to help optimize product performance and scalability, ensure that Kubernetes Metrics Server v0.3.5 or later is installed and running properly on your Kubernetes cluster.

Before you begin

For instructions about deploying Metrics Server, review the README.md file at https://github.com/kubernetes-sigs/metrics-server. For general information about Kubernetes Metrics Server, see Resource metrics pipeline.

About this task

Metrics Server is used by the Container Backup Support scheduler to determine the resources that are used by concurrent data mover instances.

If Metrics Server does not return data, a limited number of data movers are used for backup operations. This limitation might negatively impact performance.

Procedure

Verify that Metrics Server is installed and returning metrics by completing the following steps:

  1. Verify the installation by issuing the following command: 
    kubectl get deploy,svc -n kube-system | egrep metrics-server
    If Metrics Server is installed, the output is similar to the following example:
    deployment.extensions/metrics-server   1/1     1            1           3d4h
service/metrics-server   ClusterIP   198.51.100.0   <none>        443/TCP         3d4h
  2. Verify that Metrics Server is returning data for all nodes by issuing the following command: 
    kubectl get --raw "/apis/metrics.k8s.io/v1beta1/nodes"
    If Metrics Server is returning data for all nodes, the output is similar to the following example:
    {"kind":"NodeMetricsList","apiVersion":"metrics.k8s.io/v1beta1","metadata":{"selfLink":"/apis/metrics.k8s.io/v1beta1/nodes"},"items":[{"metadata":
{"name":"cirrus12","selfLink":"/apis/metrics.k8s.io/v1beta1/nodes/cirrus12",
"creationTimestamp":"2019-08-08T23:59:49Z"},"timestamp":"2019-08-08T23:59:08Z",
"window":"30s","usage":{"cpu":"1738876098n","memory":"8406880Ki"}}]}

Results

The command might fail with empty output for the "items" key. This error is likely caused by installing Metrics Server with a self-signed certificate. To resolve this issue, install Metrics Server with a correctly signed certificate that is recognized by the cluster.