Kubernetes-operator

• https://kubernetes.io/ko/docs/concepts/extend-kubernetes/operator/

• Info
  Operator는 특정 애플리케이션 컨트롤러 인 Kubernetes API를 확장하기 위해 회사에서 개발 한  CoreOS에 의해 생성됩니다 .  데이터베이스, 캐싱 및 모니터링 시스템과 같은 복잡한 상태 저장 애플리케이션을 생성, 구성 및 관리하는 데 사용됩니다.  Operator는 Kubernetes의 리소스 및 컨트롤러 개념을 기반으로하지만 일부 애플리케이션 별 전문 지식도 포함합니다. 예를 들어 데이터베이스 운영자를 생성하려면 생성 된 데이터베이스의 다양한 운영 및 유지 관리 방법에 매우 익숙해야합니다.  Operator를 만드는 열쇠는 CRD (custom resources)의 디자인입니다.

  

  • https://github.com/prometheus-operator/kube-prometheus

ServiceMonitor

• ServiceMonitor란 CRD(CustomResourceDefinition) 방식으로 Operator (코어OS 최초 시작)를 이용하여 Metric을 관리하는 방법 입니다.
• Metric 추가 작업 시 prometheus.yml 파일에 manual하게 추가하는 것이 아니고 별도의 Kubernetes Object Servicemonitor (마치 configmap, deployment 처럼)를 이용합니다.
• 
• https://www.fatalerrors.org/a/rapid-deployment-of-kubernetes-monitoring-system-kube-prometheus.html

Summary

• kube-prometheus-stack collects Kubernetes manifests, Grafana dashboards, and Prometheus rules combined with documentation and scripts to provide easy to operate end-to-end Kubernetes cluster monitoring with Prometheus using the Prometheus Operator.
• Installs the kube-prometheus stack, a collection of Kubernetes manifests, Grafana dashboards, and Prometheus rules combined with documentation and scripts to provide easy to operate end-to-end Kubernetes cluster monitoring with Prometheus using the Prometheus Operator.

Dependencies

By default this chart installs additional, dependent charts:

• kubernetes/kube-state-metrics
• prometheus-community/prometheus-node-exporter
• grafana/grafana

Guide for kube-prometheus-stack with Helm3.x

• https://artifacthub.io/packages/helm/prometheus-community/kube-prometheus-stack

sansae@win10pro-worksp:/workspaces$ vim grafana-pvc.yaml
=============================================================
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: grafana-pv-claim
  labels:
    app: grafana
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi
  storageClassName: managed-premium
=============================================================
sansae@win10pro-worksp:/workspaces$ kubectl create -f grafana-pvc.yaml
create pvc!!!



sansae@win10pro-worksp:/workspaces$ kubectl get deploy -n monitor-pga
NAME                                       READY   UP-TO-DATE   AVAILABLE   AGE
kube-prometheus-stack-grafana              1/1     1            1           6d3h


sansae@win10pro-worksp:/workspaces$ kubectl edit deploy kube-prometheus-stack-grafana -n monitor-po
=============================================================
400       volumeMounts:
       - mountPath: /var/lib/grafana
401           name: grafana-persistent-storage
-------------------------------------------------------
453
       volumes:
       - name: grafana-persistent-storage
454         persistentVolumeClaim:
455           claimName: grafana-pv-claim
=============================================================
deployment.apps/kube-prometheus-stack-grafana edited


sansae@win10pro-worksp:/workspaces$ kubectl get pvc -n monitor-po
NAME                  STATUS   VOLUME                                 CAPACITY   ACCESS MODES   STORAGECLASS      AGE
grafana-pv-claim      Bound    pvc-a13463fa-ebda-4632-a9c0-xxxxxxxx   1Gi        RWO            managed-premium   6d2h

for n in $(kubectl get namespaces -o jsonpath={..metadata.name}); do
  kubectl delete --all --namespace=$n prometheus,servicemonitor,podmonitor,alertmanager
done

kubectl delete crd alertmanagerconfigs.monitoring.coreos.com
kubectl delete crd alertmanagers.monitoring.coreos.com
kubectl delete crd podmonitors.monitoring.coreos.com
kubectl delete crd probes.monitoring.coreos.com
kubectl delete crd prometheuses.monitoring.coreos.com
kubectl delete crd prometheusrules.monitoring.coreos.com
kubectl delete crd servicemonitors.monitoring.coreos.com
kubectl delete crd thanosrulers.monitoring.coreos.com

kubectl delete clusterrole kube-prometheus-stack-grafana-clusterrole
kubectl delete clusterrole kube-prometheus-stack-kube-state-metrics
kubectl delete clusterrole kube-prometheus-stack-operator
kubectl delete clusterrole kube-prometheus-stack-operator-psp
kubectl delete clusterrole kube-prometheus-stack-prometheus
kubectl delete clusterrole kube-prometheus-stack-prometheus-psp
kubectl delete clusterrole psp-kube-prometheus-stack-kube-state-metrics
kubectl delete clusterrole psp-kube-prometheus-stack-prometheus-node-exporter

kubectl delete clusterrolebinding kube-prometheus-stack-grafana-clusterrolebinding
kubectl delete clusterrolebinding kube-prometheus-stack-kube-state-metrics
kubectl delete clusterrolebinding kube-prometheus-stack-operator
kubectl delete clusterrolebinding kube-prometheus-stack-operator-psp
kubectl delete clusterrolebinding kube-prometheus-stack-prometheus
kubectl delete clusterrolebinding kube-prometheus-stack-prometheus-psp
kubectl delete clusterrolebinding psp-kube-prometheus-stack-kube-state-metrics
kubectl delete clusterrolebinding psp-kube-prometheus-stack-prometheus-node-exporter

kubectl delete svc kube-prometheus-stack-coredns -n kube-system
kubectl delete svc kube-prometheus-stack-kube-controller-manager -n kube-system
kubectl delete svc kube-prometheus-stack-kube-etcd -n kube-system
kubectl delete svc kube-prometheus-stack-kube-proxy -n kube-system
kubectl delete svc kube-prometheus-stack-kube-scheduler -n kube-system
kubectl delete svc kube-prometheus-stack-kubelet -n kube-system
kubectl delete svc prometheus-kube-prometheus-kubelet -n kube-system

kubectl delete MutatingWebhookConfiguration kube-prometheus-stack-admission
kubectl delete ValidatingWebhookConfiguration kube-prometheus-stack-admission

https://containerjournal.com/topics/container-management/cluster-monitoring-with-prometheus-operator/

https://kangwoo.kr/2020/06/20/kubernetes-monitoring-3-kube-prometheus-%ec%84%a4%ec%b9%98-%ed%9b%84-%ed%95%b4%ec%95%bc-%ed%95%a0%ec%9d%bc/

https://waspro.tistory.com/588

https://strange-developer.tistory.com/53

https://docs.syseleven.de/metakube/de/metakube-accelerator/building-blocks/observability-monitoring/kube-prometheus-stack

https://kangwoo.kr/2020/06/13/kubernetes-monitoring-1-kube-prometheus-%EC%84%A4%EC%B9%98%ED%95%98%EA%B8%B0/