kubernetes StorageClass不保留现有数据 [英] kubernetes StorageClass does not retain existing data

问题描述

当吊舱被删除并与我的postgresql数据库一起部署后，我的Kubernetes StorageClass卷不保留现有数据.当我删除Pod时，会创建新的Pod，但是数据库为空.

My Kubernetes StorageClass volume doesn't retain existing data when the pod is deleted and deployed back with my postgresql database. When I delete the pod, the new pod is created but the database is empty.

我关注了不同版本的教程( https://kubernetes.io/docs/concepts/storage/persistent-volumes/)，但似乎无济于事.

I have followed variations of the different versions of the tutorials (https://kubernetes.io/docs/concepts/storage/persistent-volumes/) but nothing seems to work.

我粘贴了所有YAML文件，因为问题可能出在组合中.

I paste all the YAML files cause the problem might be in the combination.

storage-google.yaml

storage-google.yaml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: spingular-pvc
spec:
  storageClassName: standard
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 7Gi
---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: standard
provisioner: kubernetes.io/gce-pd
parameters:
  type: pd-standard
  zone: us-east4-a

jhipsterpress-postgresql.yml

jhipsterpress-postgresql.yml

apiVersion: v1
kind: Secret
metadata:
  name: jhipsterpress-postgresql
  namespace: default
  labels:
    app: jhipsterpress-postgresql
type: Opaque
data:
  postgres-password: NjY0NXJxd24=
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: jhipsterpress-postgresql
  namespace: default
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: jhipsterpress-postgresql
    spec:
      volumes:
      - name: data
        persistentVolumeClaim:
          claimName: spingular-pvc
      containers:
      - name: postgres
        image: postgres:10.4
        env:
        - name: POSTGRES_USER
          value: jhipsterpress
        - name: POSTGRES_PASSWORD
          valueFrom:
            secretKeyRef:
              name: jhipsterpress-postgresql
              key: postgres-password
        ports:
        - containerPort: 5432
        volumeMounts:
        - name: data
          mountPath: /var/lib/postgresql/
---
apiVersion: v1
kind: Service
metadata:
  name: jhipsterpress-postgresql
  namespace: default
spec:
  selector:
    app: jhipsterpress-postgresql
  ports:
  - name: postgresqlport
    port: 5432
  type: LoadBalancer

jhipsterpress-deployment.yml

jhipsterpress-deployment.yml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: jhipsterpress
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: jhipsterpress
      version: "v1"
  template:
    metadata:
      labels:
        app: jhipsterpress
        version: "v1"
    spec:
      initContainers:
        - name: init-ds
          image: busybox:latest
          command:
            - '/bin/sh'
            - '-c'
            - |
                while true
                do
                  rt=$(nc -z -w 1 jhipsterpress-postgresql 5432)
                  if [ $? -eq 0 ]; then
                    echo "DB is UP"
                    break
                  fi
                  echo "DB is not yet reachable;sleep for 10s before retry"
                  sleep 10
                done
      containers:
      - name: jhipsterpress-app
        image: galore/jhipsterpress
        env:
        - name: SPRING_PROFILES_ACTIVE
          value: prod
        - name: SPRING_DATASOURCE_URL
          value: jdbc:postgresql://jhipsterpress-postgresql.default.svc.cluster.local:5432/jhipsterpress
        - name: SPRING_DATASOURCE_USERNAME
          value: jhipsterpress
        - name: SPRING_DATASOURCE_PASSWORD
          valueFrom:
            secretKeyRef:
              name: jhipsterpress-postgresql
              key: postgres-password
        - name: JAVA_OPTS
          value: " -Xmx256m -Xms256m"
        resources:
          requests:
            memory: "256Mi"
            cpu: "500m"
          limits:
            memory: "512Mi"
            cpu: "1"
        ports:
        - name: http
          containerPort: 8080
        readinessProbe:
          httpGet:
            path: /management/health
            port: http
          initialDelaySeconds: 20
          periodSeconds: 15
          failureThreshold: 6
        livenessProbe:
          httpGet:
            path: /management/health
            port: http
          initialDelaySeconds: 120

jhipsterpress-service.yml

jhipsterpress-service.yml

apiVersion: v1
kind: Service
metadata:
  name: jhipsterpress
  namespace: default
  labels:
    app: jhipsterpress
spec:
  selector:
    app: jhipsterpress
  type: LoadBalancer
  ports:
  - name: http
    port: 8080

当我加入保留政策时，出现此错误:

When I included a Retain Policy I was getting this error:

@cloudshell:~ (academic-veld-230622)$ kubectl apply -f storage-google.yaml
error: error validating "storage-google.yaml": error validating data: 
ValidationError(PersistentVolumeClaim.spec): unknown field "persistentVolumeReclaimPolicy" in io.k8s.api.core.v1.PersistentVolumeClaimSpec; if you choose to ignore these errors, turn validation off with --validate=false

请，如果您知道一个有效的公共图像的完整示例(在PostgreSQL中，我可以使其与Mongo一起使用)，我将不胜感激.

Please, if you know of a complete example on a public image that works (in postgresql, I can make it work with Mongo), I will really appreciate it.

感谢所有人.

推荐答案

请注意，要实现此目的，您需要让PVC动态地设置PV以满足其要求，然后会有一个永久的

Note that for this to work you need to have your PVC dynamically provision a PV to satisfy its requirements, then there will be a permanent binding between the PVC and PV and every time your workload uses the PVC then it will use the same PV. Specifically indicated by this excerpt:

如果为新的PVC动态配置了PV，则循环将始终将该PV绑定到PVC

If a PV was dynamically provisioned for a new PVC, the loop will always bind that PV to the PVC

如果在您的情况下，PVC设置了Google永久磁盘，并且您可以验证在GCP上每次使用的PV是否相同，那么pod的启动过程可能会出现问题，因为它会删除所有数据. (为什么要使用/var/lib/postgresql/ vs /var/lib/postgresql?)

If in your case the Google Persistent Disk is being provisioned by the PVC, and you can verify that on GCP it's the same PV used every time, then it's probably an issue with the pod startup process where it's removing all the data. (Is there any reason why you are using /var/lib/postgresql/ vs /var/lib/postgresql?)

此外，persistentVolumeReclaimPolicy: Retain适用于PV，而不适用于PVC.对于动态预配置的PV，该值为Delete.在您的情况下，该设置将不适用，因为您应将动态预配置的卷绑定到您的PVC.换句话说，您不是在回收该卷.

Also, persistentVolumeReclaimPolicy: Retain applies to a PV, not a PVC. For dynamically provisioned PVs the value is Delete. In your case, it wouldn't apply because your dynamically provisioned volume should be bound to your PVC. In other words, you are not reclaiming the volume.

说了所有建议的部署数据库的方法是使用 StatefulSets 与以下 mysql 示例类似， volumeClaimTemplate.

Having said all that the recommended way to deploy a DB is using StatefulSets similar to this mysql example using a volumeClaimTemplate.

这篇关于kubernetes StorageClass不保留现有数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！