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Prerrequisites

  • Kubernetes API Connectivity
    The plugin must be able to reach API remotely in order to extract the information.
  • Permissions
    To make requests through the API, the account used to authenticate during execution requires certain permissions.

Permission Assignment

The steps to follow to create a user with sufficient permissions to obtain the monitoring data are described below. 

1. Creation of a read “Cluster role” called “​api-read-only​”: A role will be created that grants “​get​”, “​list​” and “​watch​” permissions to all resources of Kubernetes.

cat <<EOF | kubectl apply -f -
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
annotations:
rbac.authorization.kubernetes.io/autoupdate: "true"
labels:
name: ​api-read-only
rules:
- apiGroups:
- '*'
resources:
- '*'
verbs:
- get
- list
- watch
- nonResourceURLs:
- '*'
verbs:
- get
- list
- watch
EOF

2. Creation of a “​Cluster role binding​” called “​bind-api-read-only​”: The role will be linked previously created to an already existing “​service account​”.

kubectl create clusterrolebinding ​bind-api-read-only​ \
--clusterrole=​api-read-only​ \
--serviceaccount=​namespace​:user
  • Install metrics server

To install the “metrics-server” addon, it will be necessary to download it in the Kubernetes environment. You can get it from their github project:

https://github.com/kubernetes-incubator/metrics-server

kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml

You can verify that the deployment has been successful if when you launch the following command the status of your API appears as “​true​”:

kubectl get apiservices | grep metrics-server
v1beta1.metrics.k8s.io    kube-system/metrics-server True 1m

If the deployment is successful, the metrics-server API should be accessible:

​kubectl get --raw "/apis/metrics.k8s.io/v1beta1/"
{"kind":"APIResourceList","apiVersion":"v1","groupVersion":"metrics.k8s.io/v1beta1","res
ources":[{"name":"nodes","singularName":"","namespaced":false,"kind":"NodeMetrics
","verbs":["get","list"]},{"name":"pods","singularName":"","namespaced":true,"kind":"P
odMetrics","verbs":["get","list"]}]}

Additionally, after a few seconds, you should be able to obtain CPU and memory usage data for containers and nodes:

$ ​kubectl top node
NAMECPU(cores) CPU%MEMORY(bytes)MEMORY%
kube93m968Mi56%4%
$ ​kubectl top pod
NAMECPU(cores)MEMORY(bytes)
pod10m3Mi
pod20m3Mi
pod30m2Mi
pod40m3Mi
pod50m1Mi


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