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Kubernetes 存储管理

📂 devops ⏱ 3 min 403 words

Kubernetes 存储管理

存储概念

PersistentVolume (PV)

PV 是集群级别的存储资源，由管理员预先配置或使用 StorageClass 动态创建：

apiVersion: v1
kind: PersistentVolume
metadata:
  name: my-pv
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  storageClassName: standard
  hostPath:
    path: /mnt/data

PersistentVolumeClaim (PVC)

PVC 是用户对存储资源的请求：

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 5Gi
  storageClassName: standard

StorageClass

StorageClass 定义存储类型，支持动态创建 PV：

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: fast
provisioner: kubernetes.io/aws-ebs
parameters:
  type: gp2
reclaimPolicy: Retain
allowVolumeExpansion: true
volumeBindingMode: WaitForFirstConsumer

使用存储

在 Pod 中挂载 PVC

apiVersion: v1
kind: Pod
metadata:
  name: my-pod
spec:
  containers:
    - name: my-container
      image: nginx
      volumeMounts:
        - name: my-storage
          mountPath: /data
  volumes:
    - name: my-storage
      persistentVolumeClaim:
        claimName: my-pvc

在 Deployment 中使用

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
        - name: my-container
          image: my-app
          volumeMounts:
            - name: data
              mountPath: /app/data
      volumes:
        - name: data
          persistentVolumeClaim:
            claimName: my-pvc

存储访问模式

ReadWriteOnce (RWO): 单节点读写
ReadOnlyMany (ROX): 多节点只读
ReadWriteMany (RWX): 多节点读写
ReadWriteOncePod (RWOP): 单 Pod 读写

动态存储配置

使用 StorageClass

# 查看 StorageClass
kubectl get storageclass

# 设置默认 StorageClass
kubectl patch storageclass standard \
  -p '{"metadata":{"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'

创建 PVC 动态创建 PV

kubectl apply -f pvc.yaml
# PV 会自动创建并绑定
kubectl get pv
kubectl get pvc

常用操作

# 查看 PV
kubectl get pv
kubectl describe pv my-pv

# 查看 PVC
kubectl get pvc
kubectl describe pvc my-pvc

# 扩展 PVC
kubectl patch pvc my-pvc -p '{"spec":{"resources":{"requests":{"storage":"20Gi"}}}}'

# 回收 PV
kubectl patch pv my-pv -p '{"spec":{"persistentVolumeReclaimPolicy":"Delete"}}'

存储类型

NFS

apiVersion: v1
kind: PersistentVolume
metadata:
  name: nfs-pv
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteMany
  nfs:
    server: nfs-server.example.com
    path: "/exports/data"

AWS EBS

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: aws-gp2
provisioner: ebs.csi.aws.com
parameters:
  type: gp2
  fsType: ext4

本地存储

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: local-storage
provisioner: kubernetes.io/no-provisioner
volumeBindingMode: WaitForFirstConsumer

实践案例

数据库持久化存储

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-data
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 20Gi
  storageClassName: fast
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql
spec:
  replicas: 1
  selector:
    matchLabels:
      app: mysql
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
        - name: mysql
          image: mysql:8.0
          volumeMounts:
            - name: mysql-data
              mountPath: /var/lib/mysql
          env:
            - name: MYSQL_ROOT_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: mysql-secret
                  key: root-password
      volumes:
        - name: mysql-data
          persistentVolumeClaim:
            claimName: mysql-data

常见问题

PVC 一直 Pending

# 检查 PVC 状态
kubectl describe pvc my-pvc

# 检查 StorageClass
kubectl describe storageclass standard

# 检查是否有可用 PV
kubectl get pv | grep Available

PV 无法绑定

# 检查访问模式
kubectl describe pv my-pv
kubectl describe pvc my-pvc

# 检查容量
kubectl get pv -o custom-columns=NAME:.metadata.name,CAPACITY:.spec.capacity.storage

最佳实践

使用 StorageClass 实现动态存储配置
设置合理的存储容量和访问模式
定期备份重要数据
使用回收策略保护数据
考虑存储性能和成本

总结

Kubernetes 存储管理通过 PV、PVC 和 StorageClass 实现了灵活的持久化存储。合理使用存储资源可以确保应用数据的安全性和可靠性。