【掌握K8s存儲卷】輕鬆實現容器數據持久化策略

引言

在Kubernetes（K8s）中，容器作為安排利用的基本單位，其生命周期是長久的。當容器重啟或被刪除時，其中的數據會隨之喪掉。為懂得決這個成績，K8s引入了存儲卷（Volume）的不雅點，使得容器中的數據可能長久化存儲。本文將具體介紹K8s中的存儲卷範例、利用方法以及長久化戰略。

存儲卷範例

1. emptyDir

emptyDir是K8s中的一種常設存儲卷，它會在Pod被分配到節點時主動創建，當Pod被刪除時，emptyDir中的數據也會被刪除。emptyDir重要用於常設存儲，比方利用順序的緩存或旁邊數據。

apiVersion: v1
kind: Pod
metadata:
  name: example-pod
spec:
  containers:
  - name: example-container
    image: nginx
    volumeMounts:
    - name: tmp
      mountPath: /tmp
  volumes:
  - name: tmp
    emptyDir: {}

2. hostPath

hostPath容許容器拜訪宿主機的文件體系。這種方法簡單易用，但數據不會在宿主機毛病時掉掉落保護。

apiVersion: v1
kind: Pod
metadata:
  name: example-pod
spec:
  containers:
  - name: example-container
    image: nginx
    volumeMounts:
    - name: host-path
      mountPath: /data
  volumes:
  - name: host-path
    hostPath:
      path: /path/on/host

3. nfs

nfs是K8s中常用的網路文件體系，容許容器拜訪遠程nfs共享目錄。

apiVersion: v1
kind: PersistentVolume
metadata:
  name: nfs-pv
spec:
  nfs:
    path: /path/on/nfs
    server: nfs-server-ip

---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: nfs-pvc
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 1Gi

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: example-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: example
  template:
    metadata:
      labels:
        app: example
    spec:
      containers:
      - name: example-container
        image: nginx
        volumeMounts:
        - name: nfs
          mountPath: /data
      volumes:
      - name: nfs
        persistentVolumeClaim:
          claimName: nfs-pvc

4. persistentVolume (PV) 跟 persistentVolumeClaim (PVC)

PV跟PVC是K8s中更為高等的存儲卷範例，它們容許靜態分配存儲資本。

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-example
spec:
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  nfs:
    path: /path/on/nfs
    server: nfs-server-ip

---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-example
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi

長久化戰略

1. StatefulSet

StatefulSet是K8s頂用於管理有狀況利用的一種把持器。StatefulSet中的每個Pod都有牢固的網路標識符跟存儲卷，從而保證數據的長久化。

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: example-statefulset
spec:
  serviceName: "example-service"
  replicas: 1
  selector:
    matchLabels:
      app: example
  template:
    metadata:
      labels:
        app: example
    spec:
      containers:
      - name: example-container
        image: nginx
        volumeMounts:
        - name: example-pv
          mountPath: /data
  volumeClaimTemplates:
  - metadata:
      name: example-pv
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 1Gi

2. StorageClass

StorageClass是K8s頂用於靜態創建PV的資本。經由過程定義StorageClass，可能簡化PV的創建跟管理。

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: standard
provisioner: kubernetes.io/aws-ebs
parameters:
  type: gp2
reclaimPolicy: Retain
volumeBindingMode: Immediate

總結

K8s存儲卷為容器數據長久化供給了多種處理打算。經由過程公道抉擇存儲卷範例跟長久化戰略，可能輕鬆實現容器數據的長久化，進步利用的堅固性跟牢固性。