Kubernetes 영구 볼륨

apiVersion: v1
kind: Pod
metadata:
  name: emptydir-pod
spec:
  containers:
  # 첫 번째 컨테이너: 데이터 생성
  - name: writer
    image: busybox
    command: ['sh', '-c', 'echo "Hello from writer" > /data/message.txt && sleep 3600']
    volumeMounts:
    - name: shared-data
      mountPath: /data

  # 두 번째 컨테이너: 데이터 읽기
  - name: reader
    image: busybox
    command: ['sh', '-c', 'sleep 10 && cat /data/message.txt && sleep 3600']
    volumeMounts:
    - name: shared-data
      mountPath: /data

  volumes:
  - name: shared-data
    emptyDir: {}  # 빈 디렉터리 생성

volumes:
- name: cache-volume
  emptyDir:
    medium: Memory      # RAM 디스크 사용
    sizeLimit: 100Mi    # 최대 크기 제한

apiVersion: v1
kind: Pod
metadata:
  name: hostpath-pod
spec:
  containers:
  - name: nginx
    image: nginx:latest
    volumeMounts:
    - name: host-data
      mountPath: /usr/share/nginx/html  # 컨테이너 내 마운트 경로

  volumes:
  - name: host-data
    hostPath:
      path: /data/nginx    # 호스트(노드)의 경로
      type: DirectoryOrCreate  # 없으면 생성

# ⚠️ 보안 위험: 루트 디렉터리 마운트
volumes:
- name: root-access
  hostPath:
    path: /   # 위험! 전체 노드 파일시스템 접근 가능

# ✅ 권장: 필요한 디렉터리만 마운트
volumes:
- name: logs
  hostPath:
    path: /var/log/myapp
    type: DirectoryOrCreate

apiVersion: v1
kind: Pod
metadata:
  name: nfs-pod
spec:
  containers:
  - name: app
    image: nginx
    volumeMounts:
    - name: nfs-storage
      mountPath: /data

  volumes:
  - name: nfs-storage
    nfs:
      server: 192.168.1.100   # NFS 서버 IP
      path: /exports/data      # NFS 공유 경로
      readOnly: false

apiVersion: v1
kind: Pod
metadata:
  name: ebs-pod
spec:
  containers:
  - name: app
    image: nginx
    volumeMounts:
    - name: ebs-storage
      mountPath: /data

  volumes:
  - name: ebs-storage
    awsElasticBlockStore:
      volumeID: vol-0123456789abcdef0
      fsType: ext4

apiVersion: v1
kind: PersistentVolume
metadata:
  name: my-pv
  labels:
    type: local
    app: mysql
spec:
  # 스토리지 클래스 (PVC와 매칭에 사용)
  storageClassName: manual

  # 용량
  capacity:
    storage: 10Gi

  # 접근 모드
  accessModes:
    - ReadWriteOnce

  # 회수 정책
  persistentVolumeReclaimPolicy: Retain

  # 실제 스토리지 정의
  hostPath:
    path: /mnt/data
    type: DirectoryOrCreate

# NFS 기반 PV
apiVersion: v1
kind: PersistentVolume
metadata:
  name: nfs-pv
spec:
  storageClassName: nfs
  capacity:
    storage: 100Gi
  accessModes:
    - ReadWriteMany   # NFS는 다중 노드 쓰기 지원
  nfs:
    server: nfs-server.example.com
    path: /exports/data
---
# AWS EBS 기반 PV
apiVersion: v1
kind: PersistentVolume
metadata:
  name: ebs-pv
spec:
  storageClassName: aws-ebs
  capacity:
    storage: 50Gi
  accessModes:
    - ReadWriteOnce   # EBS는 단일 노드만 지원
  awsElasticBlockStore:
    volumeID: vol-0123456789abcdef0
    fsType: ext4

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-pvc
spec:
  # 스토리지 클래스 (PV와 매칭)
  storageClassName: manual

  # 접근 모드
  accessModes:
    - ReadWriteOnce

  # 요청 용량
  resources:
    requests:
      storage: 5Gi

  # 특정 PV 선택 (선택사항)
  selector:
    matchLabels:
      app: mysql

apiVersion: v1
kind: Pod
metadata:
  name: mysql-pod
spec:
  containers:
  - name: mysql
    image: mysql:8.0
    env:
    - name: MYSQL_ROOT_PASSWORD
      value: "password"
    ports:
    - containerPort: 3306
    volumeMounts:
    - name: mysql-storage
      mountPath: /var/lib/mysql   # MySQL 데이터 디렉터리

  volumes:
  - name: mysql-storage
    persistentVolumeClaim:
      claimName: my-pvc   # PVC 이름 참조

# 1. PersistentVolume 생성
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-pv
spec:
  storageClassName: manual
  capacity:
    storage: 20Gi
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  hostPath:
    path: /mnt/mysql-data
---
# 2. PersistentVolumeClaim 생성
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-pvc
spec:
  storageClassName: manual
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi
---
# 3. Deployment 생성
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql
spec:
  selector:
    matchLabels:
      app: mysql
  strategy:
    type: Recreate   # 롤링 업데이트 대신 재생성 (DB 권장)
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
      - name: mysql
        image: mysql:8.0
        env:
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-secret
              key: password
        ports:
        - containerPort: 3306
        volumeMounts:
        - name: mysql-persistent-storage
          mountPath: /var/lib/mysql
        resources:
          requests:
            memory: "512Mi"
            cpu: "250m"
          limits:
            memory: "1Gi"
            cpu: "500m"
      volumes:
      - name: mysql-persistent-storage
        persistentVolumeClaim:
          claimName: mysql-pvc
---
# 4. Service 생성
apiVersion: v1
kind: Service
metadata:
  name: mysql
spec:
  selector:
    app: mysql
  ports:
  - port: 3306
  clusterIP: None   # Headless Service
---
# 5. Secret 생성 (비밀번호)
apiVersion: v1
kind: Secret
metadata:
  name: mysql-secret
type: Opaque
data:
  password: cGFzc3dvcmQ=   # base64 encoded "password"

apiVersion: v1
kind: PersistentVolume
metadata:
  name: retain-pv
spec:
  persistentVolumeReclaimPolicy: Retain  # 보존 정책
  # ...

---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: delete-pv
spec:
  persistentVolumeReclaimPolicy: Delete  # 삭제 정책
  # ...

# PV 상태 확인
kubectl get pv

# 출력 예시
NAME       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM              STORAGECLASS
mysql-pv   20Gi       RWO            Retain           Bound       default/mysql-pvc  manual
nfs-pv     100Gi      RWX            Delete           Available                      nfs

# PV 상세 정보
kubectl describe pv mysql-pv

# AWS EBS 기반 StorageClass
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: fast-ssd
provisioner: kubernetes.io/aws-ebs   # 프로비저너
parameters:
  type: gp3                          # EBS 볼륨 타입
  fsType: ext4
  encrypted: "true"
reclaimPolicy: Delete                # 회수 정책
allowVolumeExpansion: true           # 볼륨 확장 허용
volumeBindingMode: WaitForFirstConsumer  # 파드 스케줄링 후 바인딩
---
# NFS 기반 StorageClass (NFS Provisioner 필요)
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: nfs-storage
provisioner: nfs.csi.k8s.io
parameters:
  server: nfs-server.example.com
  share: /exports
reclaimPolicy: Retain
---
# 로컬 스토리지 기반 (개발/테스트용)
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: local-storage
provisioner: kubernetes.io/no-provisioner  # 수동 프로비저닝
volumeBindingMode: WaitForFirstConsumer

# PVC에서 StorageClass 지정 → PV 자동 생성
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: dynamic-pvc
spec:
  storageClassName: fast-ssd   # StorageClass 이름
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 50Gi

# 이 PVC를 생성하면 50Gi의 gp3 EBS 볼륨이 자동으로 프로비저닝됨!

# 기본 StorageClass 확인
kubectl get storageclass

# 기본 StorageClass 설정
kubectl patch storageclass fast-ssd -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'

# 기본 StorageClass가 설정되면 storageClassName 생략 가능
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: default-pvc
spec:
  # storageClassName 생략 → 기본 StorageClass 사용
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi

# PV 목록 조회
kubectl get pv

# PV 상세 조회
kubectl describe pv <pv-name>

# PV 생성
kubectl apply -f pv.yaml

# PV 삭제
kubectl delete pv <pv-name>

# PV YAML 출력
kubectl get pv <pv-name> -o yaml

# PVC 목록 조회
kubectl get pvc

# PVC 목록 조회 (모든 네임스페이스)
kubectl get pvc --all-namespaces

# PVC 상세 조회
kubectl describe pvc <pvc-name>

# PVC 생성
kubectl apply -f pvc.yaml

# PVC 삭제
kubectl delete pvc <pvc-name>

# StorageClass 목록 조회
kubectl get storageclass
kubectl get sc

# StorageClass 상세 조회
kubectl describe sc <sc-name>