Add Service monitor

k8s/Cluster/README.md

@@ -11,9 +11,15 @@ Deploy Prometheus for monitoring in the cluster
 ```sh
 kubectl apply -f Prometheus/*
 ```
+###### note
+when we have a monitoring namespace for kubernetes we only need to apply service monitor for our service e.g:
+```sh
+kubectl apply -f service-monitor.yaml
+```
+
 ##### Step 3
 Deploy the service to cluster with horizontal pod autoscaling
 ```sh
 kubectl apply -f app-deployment.yaml
 kubectl apply -f hpa.yaml
-```
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+```

k8s/Cluster/app-deployment.yaml

@@ -2,6 +2,11 @@ apiVersion: v1 # Kubernetes API version
 kind: Service # Kubernetes resource kind we are creating
 metadata: # Metadata of the resource kind we are creating
   name: ms-demo-service
+  annotations:
+    prometheus.io/port: "ms-metrics"
+    prometheus.io/scrape: "true"
+  labels:
+    app.kubernetes.io/part-of: ms-demo-svc
 spec:
   selector:
     app: ms-demo
@@ -10,6 +15,7 @@ spec:
       port: 8080 # The port that the service is running on in the cluster
       targetPort: 8080 # The port exposed by the service
       nodePort: 30999
+      name: "ms-metrics"
   type: LoadBalancer # type of the service.
 ---
 apiVersion: apps/v1
@@ -34,9 +40,9 @@ spec:
             - containerPort: 8080 # The port that the container is running on in the cluster
           resources: # important for hpa
             limits:
-              cpu: "2"
-              memory: 2Gi
+              cpu: "1"
+              memory: 1Gi
             requests:
               cpu: 500m
-              memory: 1Gi
+              memory: 500Mi
 

k8s/Cluster/hpa.yaml

@@ -24,6 +24,12 @@ spec:
     apiVersion: apps/v1
     kind: Deployment
     name: ms-demo
+# Doc
 #  kubectl autoscale deployment ms-demo-hpa --cpu-percent=50 --min=1 --max=10 // another way to create hpa
 #  kubectl get hpa ms-demo-hpa --watch // monitor hpa
-#  kubectl scale --replicas=2 deployment.apps/ms-demo //scale manually
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+#  kubectl scale --replicas=2 deployment.apps/ms-demo //scale manually
+##  To monitor utilization:
+#  kube_horizontalpodautoscaler_status_current_replicas{horizontalpodautoscaler='ms-demo-hpa'}/
+#  kube_horizontalpodautoscaler_spec_max_replicas{horizontalpodautoscaler='ms-demo-hpa'}*100
+## To Monitor current replica
+#  kube_horizontalpodautoscaler_status_current_replicas{horizontalpodautoscaler='ms-demo-hpa'}
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k8s/Cluster/service-monitor.yaml

+# A ServiceMonitor is a Kubernetes object that defines how Prometheus should monitor a specific service running in a Kubernetes cluster.
+#ServiceMonitor allows Prometheus to automatically discover and scrape metrics from services that are running in the same Kubernetes cluster.
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  name: ms-demo-service-monitor
+  namespace: monitoring
+spec:
+  endpoints: #This field specifies the endpoints that Prometheus should scrape for metrics. You can specify the port, path, and other information for each endpoint.
+    - interval: 15s
+      port: ms-metrics
+      scrapeTimeout: 14s
+      path: /actuator/prometheus
+  namespaceSelector:
+    matchNames:
+      - default
+  selector: #This field specifies how Prometheus should discover the target service to monitor. You can use labels, namespaces, and other selectors to choose the target service.
+    matchLabels:
+      app.kubernetes.io/part-of: ms-demo-svc
+
+#ref: https://dev.to/apgapg/creating-a-service-monitor-in-k8s-nl8
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