Kubernates assing multiple endpoints

by

i have the following configurations on kubernates:

apiVersion: apps/v1beta2
kind: Deployment
metadata:
  name: {{ include "e-lucene-eva.fullname" . }}
  labels:
    app.kubernetes.io/name: {{ include "e-lucene-eva.name" . }}
    helm.sh/chart: {{ include "e-lucene-eva.chart" . }}
    app.kubernetes.io/instance: {{ .Release.Name }}
    app.kubernetes.io/managed-by: {{ .Release.Service }}
spec:
  replicas: {{ .Values.replicaCount }}
  selector:
    matchLabels:
      app.kubernetes.io/name: {{ include "e-lucene-eva.name" . }}
      app.kubernetes.io/instance: {{ .Release.Name }}
  template:
    metadata:
      labels:
        app.kubernetes.io/name: {{ include "e-lucene-eva.name" . }}
        app.kubernetes.io/instance: {{ .Release.Name }}
    spec:
      containers:
        - name: {{ .Chart.Name }}
          image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
          imagePullPolicy: {{ .Values.image.pullPolicy }}
          ports:
            - name: evaptr
              containerPort: 8089
          resources:
            resources:
            limits:
              cpu: 150m
              memory: 1528Mi
            requests:
              cpu: 100m
              memory: 664Mi


apiVersion: v1
kind: Service
metadata:
  name: st-evabot-adm-backend-service
  namespace: st-evabot
spec:
  ports:
    - targetPort: bck-port
      port: 80
      protocol: TCP
  selector:
    app: evabot
    tier: backend

but when i run kubectl get endpoints:

NAME                                       ENDPOINTS                                                    AGE
evabot-db-service                          191.255.54.169:27017                                         19h
evabot-lucene-service                      191.255.48.148:8089,191.255.54.169:8089,191.255.55.35:8089   13h

why i have 3 ip ? and other has just 1?
Another question is .. these ips are for the connections with other pods ? 

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  annotations:
    deployment.kubernetes.io/revision: "1"
  creationTimestamp: null
  generation: 1
  labels:
    app.kubernetes.io/instance: st-evabot-evabot-lucene
    app.kubernetes.io/managed-by: Tiller
    app.kubernetes.io/name: e-lucene-eva
    helm.sh/chart: e-lucene-eva-0.1.1
  name: st-evabot-evabot-lucene-e-lucene-eva
  selfLink: /apis/extensions/v1beta1/namespaces/st-evabot/deployments/st-evabot-evabot-lucene-e-lucene-eva
spec:
  progressDeadlineSeconds: 600
  replicas: 1
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      app.kubernetes.io/instance: st-evabot-evabot-lucene
      app.kubernetes.io/name: e-lucene-eva
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        app.kubernetes.io/instance: st-evabot-evabot-lucene
        app.kubernetes.io/name: e-lucene-eva
    spec:
      containers:
      - image: registry-dgt.eni.com/eni/evabot-lucene:1.0.4
        imagePullPolicy: IfNotPresent
        name: e-lucene-eva
        ports:
        - containerPort: 8089
          name: evaptr
          protocol: TCP
        resources:
          limits:
            cpu: 150m
            memory: 1528Mi
          requests:
            cpu: 100m
            memory: 664Mi
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
      dnsPolicy: ClusterFirst
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      terminationGracePeriodSeconds: 30
status: {}



evabot-adm-ui-service                      ClusterIP   191.255.46.131   <none>        3031/TCP       21h       app=evabot,tier=frontend
evabot-lucene-service                      ClusterIP   191.255.46.28    <none>        8089/TCP       2h        app=evabot
st-evabot-adm-backend-service              NodePort    191.255.45.200   <none>        80:31971/TCP   8m        app=evabot,tier=backend
st-evabot-db-service                       ClusterIP   191.255.47.200   <none>        27017/TCP      31m       app=mongo-proxy
st-evabot-evabot-db-mongodb-replicaset     ClusterIP   None             <none>        27017/TCP      3d        app=mongodb-replicaset,release=st-evabot-evabot-db
st-evabot-fe-evabot-web-apache-webserver   ClusterIP   191.255.45.37    <none>        80/TCP         1d        app=apache-webserver,release=st-evabot-fe-evabot-web
tiller-deploy                              ClusterIP   191.255.44.63    <none>        44134/TCP      6d        app=helm,name=tiller

Answer

I was not able to find neither app=evabot nor tier=frontend labels through the provided deployment manifest file, therefore the services evabot-db-service and evabot-lucene-service are exposing a different deployments(Pods).

However, you can easily retrieve information from your cluster about all components which are related to the labels app=evabot or tier=frontend:

kubectl get all -l app=evabot

kubectl get all -l tier=frontend

In general, Endpoint is the final point of your request where the Service will route network traffic to when a connection has been established to the Pods IP address. They can be auto discovered by Kubernetes with selectors or manually managed.

I assume that for evabot-lucene-service service in your example, possibly three Pods have been created by ReplicaSet, that are finally serving requests by their Endpoints:

evabot-lucene-service
191.255.48.148:8089,191.255.54.169:8089,191.255.55.35:8089

For evabot-db-service service, only one Pod represents the Endpoint.

evabot-db-service 191.255.54.169:27017

In case of any doubt or question, write a comment below this answer.

Attribution
Source : Link , Question Author : T-student , Answer Author : Nick_Kh

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