Metrics API (node/pod resource usage)

[hjacobs]

The Metrics Server (Resource Metrics API) is currently not set up, this is already mentioned as a to-do in the README:

Metrics API due to kube aggregation not being setup

Please add support for the Resource Metrics API (metrics.k8s.io/v1beta1 API version) to track node/pod resource usage and allow using kubectl top (#157) and tools like kube-ops-view.

K3s is awesome btw 😄

[reegnz]

Also realized today that the fact that metrics API is not present anything relying on HorizontalPodAutoscaling won't work either. :( That is something I ran into with trying to autoscale a deployment on k3s.

[hjacobs]

I had a similar issue with kind (Kubernetes in Docker), here how I deployed Metrics API: kubernetes-sigs/kind#398

[erikwilson]

Metrics server should work with the latest RC, but needs some extra configuration.

To verify functionality k3s should run with a --kubelet-arg="address=0.0.0.0" flag, ex:

INSTALL_K3S_VERSION=v0.4.0-rc2 ./install.sh --kubelet-arg="address=0.0.0.0"

And install metrics server using our custom deployment from the root of this repo:

kubectl apply -f recipes/metrics-server

Then after a minute test metrics scraping:

kubectl get --raw /apis/metrics.k8s.io/v1beta1/nodes

Our goal is to continue improving k3s so a default deployment of metrics-server will work with the default arguments of k3s, this is being tracked in /issues/328.

[dnoland1]

Works for me. Started up k3s using:

root@k3s-node1:~# k3s server --kubelet-arg="address=0.0.0.0"

Applied metrics-server manifests:

root@k3s-node1:~# k3s kubectl apply -f k3s/recipes/metrics-server/
clusterrole.rbac.authorization.k8s.io/system:aggregated-metrics-reader created
clusterrolebinding.rbac.authorization.k8s.io/metrics-server:system:auth-delegator created
rolebinding.rbac.authorization.k8s.io/metrics-server-auth-reader created
apiservice.apiregistration.k8s.io/v1beta1.metrics.k8s.io created
serviceaccount/metrics-server created
deployment.apps/metrics-server created
service/metrics-server created
clusterrole.rbac.authorization.k8s.io/system:metrics-server created
clusterrolebinding.rbac.authorization.k8s.io/system:metrics-server created

Able to see pod and node metrics:

root@k3s-node1:~# k3s kubectl top node
NAME        CPU(cores)   CPU%   MEMORY(bytes)   MEMORY%
k3s-node1   40m          4%     350Mi           72%
root@k3s-node1:~# k3s kubectl top pod --all-namespaces
NAMESPACE     NAME                              CPU(cores)   MEMORY(bytes)
kube-system   coredns-857cdbd8b4-dl2bx          4m           11Mi
kube-system   helm-install-traefik-s8x6m        0m           0Mi
kube-system   metrics-server-675d76bcdb-6bc26   1m           14Mi
kube-system   svclb-traefik-6cf7794986-jdpd4    0m           1Mi
kube-system   traefik-55bd9646fc-d8bc9          4m           14Mi  

[erikwilson]

Thanks for testing @dnoland1!

[hjacobs]

@erikwilson fix for the README: #355