📦 04. K8s 기본 리소스

  apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
spec:
  containers:
  - name: nginx
    image: nginx:latest
    ports:
    - containerPort: 80
  

  kubectl create -f ./nginx.yaml
  

  kubectl get pod
  

  kubectl port-forward nginx-pod 8080:80
  

  kubectl get po -o wide
  

  curl http://<Pod-IP-Address>:8080
  

  kubectl exec -it nginx-pod -- bash
  

  kubectl describe po nginx-pod
  

  kubectl logs nginx-pod
  

  apiVersion: v1
kind: Pod
metadata:
  name: goapp-pod
  labels:
    env: prod
    tier: backend
spec:
  containers:
  - image: dangtong/goapp
    name: goapp-container
    ports:
    - containerPort: 8080
      protocol: TCP
  

  kubectl apply -f ./goapp-with-label.yaml
  

  kubectl get po --show-labels
  

  kubectl get po -L env -L tier
  

  kubectl label po goapp-pod app=web
  

  kubectl label po goapp-pod app=api --overwrite
  

  kubectl label po goapp-pod app-
  

  kubectl annotate pod goapp-pod maker="dangtong" team="k8s-team"
  

  kubectl describe po goapp-pod
  

  kubectl annotate po goapp-pod maker- team-
  

  kubectl get namespace
  

  kubens
  

  kubectl get po --namespace kube-system
  

  kubectl get po -n kube-system
  

  apiVersion: v1
kind: Namespace
metadata:
  name: first-namespace
  

  kubectl create -f first-namespace.yaml
  

  kubectl get ns
  

  kubectl create ns second-namespace
  

  kubectl config set-context --current --namespace=<namespace-name>
  

  kubens
  

  kubens kube-system
  

  kubectl get po -A
  

  kubectl get all -A
  

  kubectl get po -n kube-system
  

  kubectl api-resources --namespaced=true
  

  kubectl api-resources --namespaced=false
  

  kubectl delete ns first-namespace second-namespace
  

  apiVersion: v1
kind: Pod
metadata:
  labels:
    test: liveness
  name: liveness-http
spec:
  containers:
  - name: liveness
    image: k8s.gcr.io/liveness
    args:
    - /server
    livenessProbe:
      httpGet:
        path: /healthz
        port: 8080
        httpHeaders:
        - name: Custom-Header
          value: Awesome
      initialDelaySeconds: 3
      periodSeconds: 3
  

  http.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
    duration := time.Now().Sub(started)
    if duration.Seconds() > 10 {
        w.WriteHeader(500)
        w.Write([]byte(fmt.Sprintf("error: %v", duration.Seconds())))
    } else {
        w.WriteHeader(200)
        w.Write([]byte("ok"))
    }
})
  

  kubectl create -f ./liveness-probe-pod.yaml
  

  kubectl create -f ./liveness-probe-pod.yaml
  

  kubectl describe pod liveness-http
  

  apiVersion: v1
kind: Pod
metadata:
  name: liveness-command-pod
spec:
  containers:
  - name: liveness-command
    image: busybox:latest
    command: ["/bin/sh", "-c", "touch /tmp/healthy; sleep 30; rm -rf /tmp/healthy; sleep 600"]
    livenessProbe:
      exec:
        command:
        - cat
        - /tmp/healthy
      initialDelaySeconds: 5
      periodSeconds: 5
  

  kubectl create -f ./liveness-command-pod.yaml
  

  kubectl create -f ./liveness-command-pod.yaml
  

  kubectl describe pod liveness-command-pod
  

  apiVersion: v1
kind: Pod
metadata:
  name: readiness-http-pod
spec:
  containers:
  - name: readiness-http
    image: nginx:latest
    ports:
    - containerPort: 80
    readinessProbe:
      httpGet:
        path: /
        port: 80
      initialDelaySeconds: 5
      periodSeconds: 3
      timeoutSeconds: 2
      failureThreshold: 2
  

  apiVersion: v1
kind: Pod
metadata:
  name: readiness-tcp-pod
spec:
  containers:
  - name: readiness-tcp
    image: redis:7.2
    ports:
    - containerPort: 6379
    readinessProbe:
      tcpSocket:
        port: 6379
      initialDelaySeconds: 5
      periodSeconds: 10
  

  apiVersion: v1
kind: Pod
metadata:
  name: startup-probe-pod
spec:
  containers:
  - name: startup-app
    image: nginx:latest
    ports:
    - containerPort: 80
    startupProbe:
      httpGet:
        path: /
        port: 80
      failureThreshold: 30
      periodSeconds: 10
    livenessProbe:
      httpGet:
        path: /
        port: 80
      periodSeconds: 5
    readinessProbe:
      httpGet:
        path: /
        port: 80
      periodSeconds: 3
  

  # Pod 상태 확인
kubectl get po

# Pod 상세 정보 확인 (Probe 상태 포함)
kubectl describe po <pod-name>

# Pod 로그 확인
kubectl logs <pod-name>

# Pod 이벤트 확인
kubectl get events --sort-by='.lastTimestamp'
  

  # 1. Pod 생성
kubectl apply -f liveness-demo.yaml

# 2. Pod 상태 모니터링
kubectl get po -w

# 3. Pod 상세 정보 확인
kubectl describe po liveness-demo

# 4. Pod 로그 확인
kubectl logs liveness-demo

# 5. Pod 삭제
kubectl delete po liveness-demo
  

  apiVersion: v1
kind: ReplicationController
metadata:
  name: goapp-rc
spec:
  replicas: 3
  selector:
    app: goapp
  template:
    metadata:
      name: goapp-pod
      labels:
        tier: forntend
        app: goapp
        env: prod
        priority:  high
    spec:
      containers:
      - name: goapp-container
        image: dangtong/goapp
        ports:
        - containerPort: 8080
  

  kubectl get po,rc
  

  kubectl delete pod goapp-rc-<random-hash>
  

  kubectl get pod --show-labels
  

  kubectl label pod goapp-rc-szv2r app=goapp-exit --overwrite
  

  kubectl get po
  

  kubectl edit rc goapp-rc
  

  template:
  metadata:
    creationTimestamp: null
    labels:
      app: goapp
    name: goapp-pod
  spec:
    containers:
    - image: dangtong/goapp-v2 # 이부분을 변경 합닏다.(기존 : dangtong/goapp)
      imagePullPolicy: Always
      name: goapp-container
  

  kubectl get pod
  

  
```bash
kubectl get po -o wide
  

  kubectl scale rc goapp-rc --replicas=5
  

  kubectl get po 
  

  kubectl delete rc goapp-rc --cascade=orphan
  

  kubectl delete rc goapp-rc
  

  apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: frontend
  labels:
    app: guestbook
    tier: frontend
spec:
  replicas: 3
  selector:
    matchLabels:
      tier: frontend
    matchExpressions:
      - {key: env, operator: In, values: [prod]}
      - {key: priority, operator: NotIn, values: [low]}
  template:
    metadata:
      labels:
        tier: frontend
        env: prod
        priority: high
    spec:
      containers:
      - name: nginx-frontend
        image: nginx:1.29
        ports:
        - containerPort: 80
  

  kubectl apply -f ./rs.yml
  

  kubectl get po -o wide
  

  kubectl get rs -o wide
  

  kubectl get po --show-labels
  

  apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: goapp-on-ssd
spec:
  selector:
    matchLabels:
      app: goapp-pod
  template:
    metadata:
      labels:
        app: goapp-pod
    spec:
      nodeSelector:
        disk: ssd
      containers:
      - name: goapp-container
        image: dangtong/goapp
  

  kubectl apply -f ./ds.yaml
  

  kubectl get po,ds
  

  kubectl get no 
  

  kubectl label node <node-name> disk=ssd
  

  kubectl get ds -o wide
  

  apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.29
        ports:
        - containerPort: 80
  

  kubectl apply -f nginx-deployment.yaml
kubectl get deployment
kubectl get pods -l app=nginx
  

  # kubectl set image 명령어 사용 (change cause 포함)
kubectl set image deployment/nginx-deployment nginx=nginx:1.14.2 --record

# 또는 YAML 파일 수정 후 적용 (change cause 포함)
kubectl apply -f nginx-deployment-v2.yaml --record
  

  # Annotate를 사용한 change cause 설정 (권장 방법)
kubectl annotate deployment/nginx-deployment kubernetes.io/change-cause="Update to nginx 1.30 for performance improvements"
  

  # 업데이트 상태 확인
kubectl rollout status deployment/nginx-deployment

# 업데이트 이력 확인 (change cause 포함)
kubectl rollout history deployment/nginx-deployment

# 상세 이력 확인
kubectl rollout history deployment/nginx-deployment --revision=2

# 상세 정보 확인
kubectl describe deployment nginx-deployment
  

  # 이력 확인 (change cause 표시)
kubectl rollout history deployment/nginx-deployment

# 출력 예시:
# REVISION  CHANGE-CAUSE
# 1         kubectl apply --filename=nginx-deployment.yaml --record=true
# 2         kubectl set image deployment/nginx-deployment nginx=nginx:1.30 --record=true
# 3         kubectl set image deployment/nginx-deployment nginx=nginx:1.31 --record=true
  

  # 이전 버전으로 롤백
kubectl rollout undo deployment/nginx-deployment

# 특정 버전으로 롤백
kubectl rollout undo deployment/nginx-deployment --to-revision=2
  

  # 롤백 상태 확인
kubectl rollout status deployment/nginx-deployment

# 롤백 이력 확인
kubectl rollout history deployment/nginx-deployment
  

  # 스케일 아웃
kubectl scale deployment nginx-deployment --replicas=5

# 스케일 인
kubectl scale deployment nginx-deployment --replicas=2
  

  kubectl get deployment nginx-deployment
kubectl get pods -l app=nginx
  

  apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 5
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.29
        ports:
        - containerPort: 80
  

  kubectl set image deployment/nginx-deployment nginx=nginx:1.14.2 --record
  

  kubectl rollout status deployment/nginx-deployment
  

  kubectl get po -w
  

  kubectl get po
  

  apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment-recreate
spec:
  replicas: 3
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.29
        ports:
        - containerPort: 80
  

  # 리소스 삭제
kubectl delete deployment nginx-deployment
kubectl delete deployment nginx-deployment-recreate
kubectl delete deployment httpd-deployment
  

  // docker/app.js
const http = require('http');
const os = require('os');
const fs = require('fs');

const dataFile = "/var/data/kubia.txt";
const port  = 8080;

// 파일 존재  유/무 검사
function fileExists(file) {
  try {
    fs.statSync(file);
    return true;
  } catch (e) {
    return false;
  }
}

var handler = function(request, response) {
//  POST 요청일 경우 BODY에 있는 내용을 파일에 기록 함
  if (request.method == 'POST') {
    var file = fs.createWriteStream(dataFile);
    file.on('open', function (fd) {
      request.pipe(file);
      console.log("New data has been received and stored.");
      response.writeHead(200);
      response.end("Data stored on pod " + os.hostname() + "\n");
    });
// GET 요청일 경우 호스트명과 파일에 기록된 내용을 반환 함
  } else {
    var data = fileExists(dataFile) ? fs.readFileSync(dataFile, 'utf8') : "No data posted yet";
    response.writeHead(200);
    response.write("You've hit " + os.hostname() + "\n");
    response.end("Data stored on this pod: " + data + "\n");
  }
};

var www = http.createServer(handler);
www.listen(port);
  

  # docker/Dockerfile
FROM node:7
ADD app.js /app.js
ENTRYPOINT ["node", "app.js"]
  

  
docker build <Docker-ID>/nodejs:sfs . --push
docker buildx build  --platform linux/amd64,linux/arm64  -t <Docker-ID>/nodejs:sfs . --push
docker login -u <Docker-ID>
docker push <Docker-ID>/nodejs:sfs
  

  # kubetemp/sts.yml
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: nodejs-sfs
spec:
  selector:
    matchLabels:
      app: nodejs-sfs
  serviceName: nodejs-sfs
  replicas: 2
  template:
    metadata:
      labels:
        app: nodejs-sfs
    spec:
      containers:
      - name: nodejs-sfs
        image: <Your-Docker-ID>/nodejs:sfs
        ports:
        - name: http
          containerPort: 8080
        volumeMounts:
        - name: data
          mountPath: /var/data
  volumeClaimTemplates:
  - metadata:
      name: data
    spec:
      resources:
        requests:
          storage: 1Mi
      accessModes:
      - ReadWriteOnce
      storageClassName: gp2
  

  kubectl apply -f ./sts.yml
  

  kubectl get po -w
  

  # kubetemp/lb.yml
apiVersion: v1
kind: Service
metadata:
    name: nodesjs-sfs-lb
    annotations:
      service.beta.kubernetes.io/aws-load-balancer-type: external
      service.beta.kubernetes.io/aws-load-balancer-nlb-target-type: ip
      service.beta.kubernetes.io/aws-load-balancer-scheme: internet-facing
spec:
    type: LoadBalancer
    sessionAffinity: None
    ports:
    - port: 80
      targetPort: 8080
    selector:
        app: nodejs-sfs
  

  kubectl apply -f ./lb.yml
  

  kubectl get svc
  

  aws elbv2 describe-load-balancers
  

  curl http://<public-domain>
  

  curl -X POST -d "hi, my name is dangtong-1" <public-domain>
curl -X POST -d "hi, my name is dangtong-2" <public-domain>
curl -X POST -d "hi, my name is dangtong-3" <public-domain>
curl -X POST -d "hi, my name is dangtong-4" <public-domain>
curl -X POST -d "hi, my name is dangtong-5" <public-domain>
  

  kubectl create namespace statefulset-lab
kubectl config set-context --current --namespace=statefulset-lab
  

  # StatefulSet 상태 확인
kubectl get statefulset

# Pod 상태 확인
kubectl get pods

# PVC 확인 (AWS EBS 볼륨 확인)
kubectl get pvc
kubectl describe pvc www-web-0

# EBS 볼륨 확인 (AWS CLI)
aws ec2 describe-volumes --filters "Name=tag:kubernetes.io/cluster/*,Values=owned" --query 'Volumes[*].[VolumeId,Size,State]' --output table

# Pod 이름 패턴 관찰
kubectl get pods -l app=nginx

# StorageClass 확인
kubectl get storageclass
kubectl describe storageclass gp2

# 문제 해결: PVC 바인딩 상태 확인
kubectl get pvc -o wide
kubectl describe pvc www-web-0

# EBS CSI Driver 상태 확인
kubectl get pods -n kube-system | grep ebs-csi
kubectl logs -n kube-system deployment/ebs-csi-controller

# 노드에 EBS CSI Driver 설치 확인
kubectl get pods -n kube-system | grep ebs-csi-node
  

  # Service 배포
kubectl apply -f nginx-headless-service.yaml

# DNS 조회 테스트
kubectl run test-dns --image=busybox --rm -it --restart=Never -- nslookup nginx

# 개별 Pod DNS 조회
kubectl run test-pod-dns --image=busybox --rm -it --restart=Never -- nslookup web-0.nginx.statefulset-lab.svc.cluster.local
kubectl run test-pod-dns --image=busybox --rm -it --restart=Never -- nslookup web-1.nginx.statefulset-lab.svc.cluster.local
kubectl run test-pod-dns --image=busybox --rm -it --restart=Never -- nslookup web-2.nginx.statefulset-lab.svc.cluster.local
  

  # 각 Pod에 고유한 데이터 쓰기
kubectl exec web-0 -- sh -c "echo 'Data from web-0 at $(date)' > /usr/share/nginx/html/index.html"
kubectl exec web-1 -- sh -c "echo 'Data from web-1 at $(date)' > /usr/share/nginx/html/index.html"
kubectl exec web-2 -- sh -c "echo 'Data from web-2 at $(date)' > /usr/share/nginx/html/index.html"

# 각 Pod의 데이터 확인
kubectl exec web-0 -- cat /usr/share/nginx/html/index.html
kubectl exec web-1 -- cat /usr/share/nginx/html/index.html
kubectl exec web-2 -- cat /usr/share/nginx/html/index.html
  

  # web-0 Pod 삭제 (재시작 시뮬레이션)
kubectl delete pod web-0

# Pod 재생성 대기
kubectl wait --for=condition=ready pod web-0

# 데이터 지속성 확인
kubectl exec web-0 -- cat /usr/share/nginx/html/index.html
  

  # StatefulSet을 5개로 확장
kubectl scale statefulset web --replicas=5

# 새로운 Pod들의 데이터 확인
kubectl exec web-3 -- cat /usr/share/nginx/html/index.html
kubectl exec web-4 -- cat /usr/share/nginx/html/index.html

# 다시 3개로 축소
kubectl scale statefulset web --replicas=3
  

  # 기존 StatefulSet 삭제
kubectl delete statefulset web
kubectl delete service nginx

# 새로운 StatefulSet 배포
kubectl apply -f advanced-statefulset.yaml
kubectl apply -f nginx-advanced-service.yaml

# 상태 확인
kubectl get statefulset
kubectl get pods
kubectl get pvc

# EBS 볼륨 확인
kubectl describe pvc www-web-advanced-0
kubectl describe pvc config-web-advanced-0

# AWS EBS 볼륨 상태 확인
aws ec2 describe-volumes --filters "Name=tag:kubernetes.io/cluster/*,Values=owned" --query 'Volumes[*].[VolumeId,Size,State,VolumeType]' --output table

# 헬스체크 테스트
kubectl logs web-advanced-0
kubectl describe pod web-advanced-0
kubectl exec web-advanced-0 -- env | grep NGINX

# 리소스 사용량 확인
kubectl top pods -l app=nginx-advanced
  

  # 이미지를 nginx:1.22로 업데이트
kubectl set image statefulset/web-advanced nginx=nginx:1.22

# 업데이트 진행 상황 확인
kubectl rollout status statefulset/web-advanced

# Pod 상태 확인
kubectl get pods -l app=nginx-advanced
  

  # partition을 1로 설정하여 web-0만 업데이트
kubectl patch statefulset web-advanced -p '{"spec":{"updateStrategy":{"rollingUpdate":{"partition":1}}}}'

# 이미지를 nginx:1.23으로 업데이트
kubectl set image statefulset/web-advanced nginx=nginx:1.23

# 업데이트된 Pod 확인
kubectl get pods -l app=nginx-advanced
  

  # 이전 버전으로 롤백
kubectl rollout undo statefulset/web-advanced

# 롤백 상태 확인
kubectl rollout status statefulset/web-advanced
  

  # 모든 리소스 삭제
kubectl delete statefulset --all
kubectl delete service --all
kubectl delete pvc --all

# EBS 볼륨 정리 확인 (삭제되지 않은 볼륨이 있을 수 있음)
aws ec2 describe-volumes --filters "Name=tag:kubernetes.io/cluster/*,Values=owned" --query 'Volumes[*].[VolumeId,Size,State]' --output table

# 네임스페이스 삭제
kubectl delete namespace statefulset-lab

# AWS EBS 볼륨 수동 삭제 (필요시)
# aws ec2 delete-volume --volume-id vol-xxxxxxxxx