引言

存储是Kubernetes的重要组成部分。本文介绍K8s的存储管理机制。

一、Volume类型

1.1 EmptyDir

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apiVersion: v1
kind: Pod
metadata:
  name: test-pod
spec:
  containers:
  - name: app
    image: nginx
    volumeMounts:
    - name: cache
      mountPath: /cache
  volumes:
  - name: cache
    emptyDir: {}

1.2 HostPath

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volumes:
- name: data
  hostPath:
    path: /data
    type: Directory

1.3 ConfigMap

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volumes:
- name: config
  configMap:
    name: app-config

1.4 Secret

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volumes:
- name: secret
  secret:
    secretName: app-secret

二、PV和PVC

2.1 PersistentVolume

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apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-nfs
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain
  nfs:
    server: 192.168.1.100
    path: /data

2.2 PersistentVolumeClaim

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apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-nfs
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 5Gi

2.3 在Pod中使用PVC

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

三、StorageClass

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apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: fast-ssd
provisioner: kubernetes.io/aws-ebs
parameters:
  type: gp2
  fsType: ext4
reclaimPolicy: Delete
volumeBindingMode: WaitForFirstConsumer

动态供应PVC

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apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: dynamic-pvc
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: fast-ssd
  resources:
    requests:
      storage: 10Gi

四、StatefulSet存储

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apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mysql
spec:
  serviceName: mysql
  replicas: 3
  selector:
    matchLabels:
      app: mysql
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
      - name: mysql
        image: mysql:8.0
        volumeMounts:
        - name: data
          mountPath: /var/lib/mysql
  volumeClaimTemplates:
  - metadata:
      name: data
    spec:
      accessModes: ["ReadWriteOnce"]
      storageClassName: fast-ssd
      resources:
        requests:
          storage: 10Gi

五、备份与恢复

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# 使用Velero备份
velero backup create my-backup --include-namespaces default

# 恢复
velero restore create --from-backup my-backup

# 定时备份
velero schedule create daily-backup --schedule="0 1 * * *"

总结

Kubernetes存储核心：

  1. Volume：临时存储
  2. PV/PVC：持久化存储
  3. StorageClass：动态供应
  4. StatefulSet：有状态应用

参考资料