Get metrics from pod with docker for mac

3/12/2019

I try to use Horizontal Pod Autosclaer for nginx pod.

When I describe my hpa I have this message horizontal-pod-autoscaler failed to get cpu utilization: unable to get metrics for resource cpu: unable to fetch metrics from resource metrics API: the server could not find the requested resource

I use docker for mac. I don't know if it can have an impact

My deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: demo-app
spec:
 selector:
   matchLabels:
     run: demo-app
 replicas: 1
 template:
   metadata:
     labels:
       run: demo-app
   spec:
  containers:
    - name: demo-app
      image: my-demo-app:v3
      imagePullPolicy: Never
      resources:
        requests:
          cpu: 250m
        limits:
          cpu: 300m
      ports:
        - containerPort: 80

My HPA

apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
 name: demo-app-hpa
 namespace: default
spec:
 scaleTargetRef:
   apiVersion: apps/v1
   kind: Deployment
   name: demo-app
 minReplicas: 1
 maxReplicas: 3
 targetCPUUtilizationPercentage: 3

Output of kubectl get hpa command :

NAME           REFERENCE             TARGETS        MINPODS   MAXPODS   REPLICAS   AGE
demo-app-hpa   Deployment/demo-app   <unknown>/3%   1         3         1          20m

Output of kubectl get --raw /apis/metrics.k8s.io/v1beta1 command

{"kind":"APIResourceList","apiVersion":"v1","groupVersion":"metrics.k8s.io/v1beta1","resources":[{"name":"nodes","singularName":"","namespaced":false,"kind":"NodeMetrics","verbs":["get","list"]},{"name":"pods","singularName":"","namespaced":true,"kind":"PodMetrics","verbs":["get","list"]}]}

I configure metric-server with this but not work

Scaling active is set to False. I think it's the problem but I don't know how change value

-- M.Hol
docker-for-mac
kubectl
kubernetes
minikube

1 Answer

3/12/2019

Looks like you are missing metrics server.

The HorizontalPodAutoscaler normally fetches metrics from a series of aggregated APIs (metrics.k8s.io, custom.metrics.k8s.io, and external.metrics.k8s.io). The metrics.k8s.io API is usually provided by metrics-server, which needs to be launched separately. See metrics-server for instructions. The HorizontalPodAutoscaler can also fetch metrics directly from Heapster.

You can check if there are metrics deployed by kubectl get --raw /apis/metrics.k8s.io/v1beta1.

To install metrics-server just clone the repo and run kubectl create -f deploy/1.8+/

If you still have the issue I recommend checking Docker Kubernetes (Mac) - Autoscaler unable to find metrics.

-- Crou
Source: StackOverflow