service

Pod

apiVersion: v1
kind: Pod
metadata:
  name: pod-1
  labels:
     app: pod
spec:
  nodeSelector:
    kubernetes.io/hostname: k8s-node1
  containers:
  - name: container
    image: kubetm/app
    ports:
    - containerPort: 8080

Service

apiVersion: v1
kind: Service
metadata:
  name: svc-1
spec:
  selector:
    app: pod
  ports:
  - port: 9000
    targetPort: 8080

apiVersion: v1
kind: Service
metadata:
  name: svc-2
spec:
  selector:
    app: pod
  ports:
  - port: 9000
    targetPort: 8080
    nodePort: 30000
  type: NodePort
  externalTrafficPolicy: Local

apiVersion: v1
kind: Service
metadata:
  name: svc-3
spec:
  selector:
    app: pod
  ports:
  - port: 9000
    targetPort: 8080
  type: LoadBalancer  

NodePort
Node Port의 범위 : 30000~32767

Ip 재생성 시 변경되는 데 여기 ip주소를 headless, dns server가 podA에게 전달하는 형식

DNS SERVER 이용

Headless

기본구조

1-1) Service

apiVersion: v1
kind: Service
metadata:
  name: clusterip1
spec:
  selector:
    svc: clusterip
  ports:
  - port: 80
    targetPort: 8080
    
1-2) Pod

apiVersion: v1
kind: Pod
metadata:
  name: pod1
  labels:
    svc: clusterip
spec:
  containers:
  - name: container
    image: kubetm/app
    
1-3) Request Pod

apiVersion: v1
kind: Pod
metadata:
  name: request-pod
spec:
  containers:
  - name: container
    image: kubetm/init
    
    
    
kubectl exec request-pod -it /bin/bash
nslookup

nslookup clusterip1
nslookup clusterip1.default.svc.cluster.local
curl

curl clusterip1/hostname
curl clusterip1.default.svc.cluster.local/hostname

headless 구조

2-1) Service

apiVersion: v1
kind: Service
metadata:
  name: headless1
spec:
  selector:
    svc: headless
  ports:
    - port: 80
      targetPort: 8080    
  clusterIP: None
  
2-2) Pod

apiVersion: v1
kind: Pod
metadata:
  name: pod4
  labels:
    svc: headless
spec:
  hostname: pod-a
  subdomain: headless1
  containers:
  - name: container
    image: kubetm/app

Nslookup

nslookup headless1
nslookup pod-a.headless1
nslookup pod-b.headless1

Curl

curl pod-a.headless1:8080/hostname
curl pod-b.headless1:8080/hostname

clusterIp None으로 주기 때문에 IP생성이 안됨

Endpoints, Externalname

endpoints

3-1) Service

apiVersion: v1
kind: Service
metadata:
  name: endpoint1
spec:
  selector:
    svc: endpoint
  ports:
  - port: 8080
  
3-2) Pod

apiVersion: v1
kind: Pod
metadata:
  name: pod7
  labels:
    svc: endpoint
spec:
  containers:
  - name: container
    image: kubetm/app
    

kubectl describe endpoints endpoint1

4-1) Service

apiVersion: v1
kind: Service
metadata:
  name: endpoint2
spec:
  ports:
  - port: 8080
  
4-2) Pod

apiVersion: v1
kind: Pod
metadata:
  name: pod9
spec:
  containers:
  - name: container
    image: kubetm/app
    
4-3) Endpoint

apiVersion: v1
kind: Endpoints
metadata:
  name: endpoint2
subsets:
 - addresses:
   - ip: 20.109.5.12
   ports:
   - port: 8080
   
   

curl endpoint2:8080/hostname

5-1) Service

apiVersion: v1
kind: Service
metadata:
  name: endpoint3
spec:
  ports:
  - port: 80
Github - Ip Address

nslookup https://www.github.com

curl -O 185.199.110.153:80/kubetm/kubetm.github.io/blob/master/sample/practice/intermediate/service-sample.md

5-2) Endpoint

apiVersion: v1
kind: Endpoints
metadata:
  name: endpoint3
subsets:
 - addresses:
   - ip: 185.199.110.153
   ports:
   - port: 80

curl -O endpoint3/kubetm/kubetm.github.io/blob/master/sample/practice/intermediate/service-sample.md

6-1) Service

apiVersion: v1
kind: Service
metadata:
 name: externalname1
spec:
 type: ExternalName
 externalName: github.github.io

curl -O externalname1/kubetm/kubetm.github.io/blob/master/sample/practice/intermediate/service-sample.md

yaml

Service
apiVersion: v1
kind: Service
metadata:
  name: headless1
spec:
  selector:             # 생략시 Endpoints 직접 생성해서 사용
    svc: headless
  ports:
    - port: 80
      targetPort: 8080    
  clusterIP: None       # headless 서비스  
  type: ExternalName    # ExternalName Service 설정시 사용
  externalName: github.github.io  # ExternalName사용시 연결 Domain지정
Endpoints
apiVersion: v1
kind: Endpoints
metadata:
  name: headless1       # Service의 이름과 동일하게 지정
subsets:
 - addresses:
   - ip: 20.109.5.12    # Pod의 ClusterIp
   ports:
   - port: 8080         # Pod의 Container Port
Pod
apiVersion: v1
kind: Pod
metadata:
  name: pod4
  labels:
    svc: headless
spec:
  hostname: pod-a       # 호스트네임 설정, 생략시 Pod Name이 적용됨
  subdomain: headless1  # headless 서비스 사용시 Service의 이름으로 지정
  containers:
  - name: container
    image: kubetm/app