Kubernetes not able to find metric-server api.I am using Kubernetes with Docker on Mac. I was trying to do HPA from following example [https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale-walkthrough/]. However, when I execute command kubectl get hpa, My target still was unknown. Then I tried, kubectl describe hpa. Which gave me error like below:
Name: php-apache
Namespace: default
Labels: <none>
Annotations: <none>
CreationTimestamp: Sun, 07 Oct 2018 12:36:31 -0700
Reference: Deployment/php-apache
Metrics: ( current / target )
resource cpu on pods (as a percentage of request): <unknown> / 5%
Min replicas: 1
Max replicas: 10
Conditions:
Type Status Reason Message
---- ------ ------ -------
AbleToScale True SucceededGetScale the HPA controller was able to get the target's current scale
ScalingActive False FailedGetResourceMetric the HPA was unable to compute the replica count: unable to get metrics for resource cpu: no metrics returned from resource metrics API
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Warning FailedComputeMetricsReplicas 1h (x34 over 5h) horizontal-pod-autoscaler failed to get cpu utilization: unable to get metrics for resource cpu: no metrics returned from resource metrics API
Warning FailedGetResourceMetric 1m (x42 over 5h) horizontal-pod-autoscaler unable to get metrics for resource cpu: no metrics returned from resource metrics API
I am using [https://github.com/kubernetes-incubator/metrics-server] as suggested in Kubernetes documentation. I also tried doing same just using Minikube. But that also didn't work.
Running kubectl get --raw /apis/metrics.k8s.io/v1beta1/nodes outputs :
{
"kind": "NodeMetricsList",
"apiVersion": "metrics.k8s.io/v1beta1",
"metadata": {
"selfLink": "/apis/metrics.k8s.io/v1beta1/nodes"
},
"items": []
}
I know this is a late answer, but I have had some issues with Docker Kubernetes and Autoscaler myself without finding a good answer on the internet. After many days of debugging, I found out that there were some connectivity issues with the metrics-server (couldn't connect to the pods).
I turned off TLS in metrics-server and it started working.. I answered my own post here if someone else is experiencing the same issue:
When using minikube 1.4.0, there is no need to do anything else than minikube start: kubectl top node/pod should work out-of-the box.
Solution(if using Minikube):
Changed context of Kubernetes to Minikube.
Enabled metrics-server and Disabled heapster in minikube.
minikube addons disable heapster
minikube addons enable metrics-server
Deploy metrics-server in your cluster using the following steps:
git clone https://github.com/kubernetes-incubator/metrics-server.git
cd metrics-server
kubectl create -f deploy/1.7/ (if Kubernetes version 1.7)
OR
kubectl create -f deploy/1.8+/(if Kubernetes version 1.8+)
Start minikube dashboad and minikube service [your service].
Try kubectl top node.
I found this (https://kubernetes.io/docs/tasks/configure-pod-container/assign-memory-resource/) resource helpful.