minikube挂载本地目录上的KubeDB

Question

我试图在minikube上使用kubedb运行postgres，当我从本地目录(位于我的Mac上)挂载我的数据时，当pod运行时，我没有得到预期的行为，发生了两件事:一是挂载显然不在那里，二是我看到了错误pod has unbound immediate PersistentVolumeClaims

首先，下面是我的yaml文件：

apiVersion: v1
kind: PersistentVolume
metadata:
  name: adminvol
  namespace: demo
  labels:
    release: development
spec:
  capacity:
    storage: 2Gi
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  hostPath:
    path: /Users/myusername/local_docker_poc/admin/lib/postgresql/data

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  namespace: demo
  name: adminpvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 2Gi
  selector:
    matchLabels:
      release: development

apiVersion: kubedb.com/v1alpha1
kind: Postgres
metadata:
  name: quick-postgres
  namespace: demo
spec:
  version: "10.2-v2"
  storageType: Durable
  storage:
    accessModes:
    - ReadWriteMany
    resources:
      requests:
        storage: 1Gi
  volumeMounts:
    - mountPath: /busy
      name: naim
      persistentVolumeClaim:
        claimName: adminpvc
  terminationPolicy: WipeOut

根据下面答案中反映的this，我已经从我所有的yaml文件中删除了storageClass。

describe pod如下所示：

Name:               quick-postgres-0
Namespace:          demo
Priority:           0
PriorityClassName:  <none>
Node:               minikube/10.0.2.15
Start Time:         Wed, 25 Sep 2019 22:18:44 +0300
Labels:             controller-revision-hash=quick-postgres-5d5bcc4698
                    kubedb.com/kind=Postgres
                    kubedb.com/name=quick-postgres
                    kubedb.com/role=primary
                    statefulset.kubernetes.io/pod-name=quick-postgres-0
Annotations:        <none>
Status:             Running
IP:                 172.17.0.7
Controlled By:      StatefulSet/quick-postgres
Containers:
  postgres:
    Container ID:  docker://6bd0946f8197ddf1faf7b52ad0da36810cceff4abb53447679649f1d0dba3c5c
    Image:         kubedb/postgres:10.2-v3
    Image ID:      docker-pullable://kubedb/postgres@sha256:9656942b2322a88d4117f5bfda26ee34d795cd631285d307b55f101c2f2cb8c8
    Port:          5432/TCP
    Host Port:     0/TCP
    Args:
      leader_election
      --enable-analytics=true
      --logtostderr=true
      --alsologtostderr=false
      --v=3
      --stderrthreshold=0
    State:          Running
      Started:      Wed, 25 Sep 2019 22:18:45 +0300
    Ready:          True
    Restart Count:  0
    Environment:
      APPSCODE_ANALYTICS_CLIENT_ID:  90b12fedfef2068a5f608219d5e7904a
      NAMESPACE:                     demo (v1:metadata.namespace)
      PRIMARY_HOST:                  quick-postgres
      POSTGRES_USER:                 <set to the key 'POSTGRES_USER' in secret 'quick-postgres-auth'>      Optional: false
      POSTGRES_PASSWORD:             <set to the key 'POSTGRES_PASSWORD' in secret 'quick-postgres-auth'>  Optional: false
      STANDBY:                       warm
      STREAMING:                     asynchronous
      LEASE_DURATION:                15
      RENEW_DEADLINE:                10
      RETRY_PERIOD:                  2
    Mounts:
      /dev/shm from shared-memory (rw)
      /var/pv from data (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from quick-postgres-token-48rkd (ro)
Conditions:
  Type              Status
  Initialized       True
  Ready             True
  ContainersReady   True
  PodScheduled      True
Volumes:
  data:
    Type:       PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
    ClaimName:  data-quick-postgres-0
    ReadOnly:   false
  shared-memory:
    Type:       EmptyDir (a temporary directory that shares a pod's lifetime)
    Medium:     Memory
    SizeLimit:  <unset>
  quick-postgres-token-48rkd:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  quick-postgres-token-48rkd
    Optional:    false
QoS Class:       BestEffort
Node-Selectors:  <none>
Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s
                 node.kubernetes.io/unreachable:NoExecute for 300s
Events:
  Type     Reason            Age   From               Message
  ----     ------            ----  ----               -------
  Warning  FailedScheduling  39s   default-scheduler  pod has unbound immediate PersistentVolumeClaims
  Normal   Scheduled         39s   default-scheduler  Successfully assigned demo/quick-postgres-0 to minikube
  Normal   Pulled            38s   kubelet, minikube  Container image "kubedb/postgres:10.2-v3" already present on machine
  Normal   Created           38s   kubelet, minikube  Created container
  Normal   Started           38s   kubelet, minikube  Started container

我按照官方手册关于如何挂载pvc here进行调试，我使用相同的pv和pvc挂载了一个简单的busybox容器，它工作得很好，也就是说，我可以看到里面有数据的挂载：

apiVersion: v1
kind: Pod
metadata:
  name: busybox
  namespace: demo
spec:
  containers:
    - name: busybox
      image: busybox
      command:
        - sleep
        - "3600"
      volumeMounts:
        - mountPath: /busy
          name: adminpvc
  volumes:
    - name: adminpvc
      persistentVolumeClaim:
        claimName: adminpvc

我自己的pod和KubeDB的唯一不同之处在于我把pod放在PV和PVC里(据我所知，后面有一个状态设置)。如果我删除存储类，我将看到容器内的挂载点，但它是空的并且没有数据

Answer 1

Remove the storageClass-line from the PersistentVolume

在minikube中，尝试如下所示：

以下是elasticsearch的示例

apiVersion: v1
kind: PersistentVolume
metadata:
  name: elasticsearch
spec:
  capacity:
    storage: 400Mi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/data/elasticsearch/"

有关更多详细信息，您也可以查看以下内容：pod has unbound PersistentVolumeClaims

编辑：

检查可用的storageclasses

kubectl get storageclass

对于PV卷

kind: PersistentVolume
apiVersion: v1
metadata:
  name: postgres-pv
  labels:
    type: local
spec:
  storageClassName: manual
  capacity:
    storage: 2Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: /data/postgres-pv

PVC文件

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: postgres-pvc
  labels:
    type: local
spec:
  storageClassName: manual
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 2Gi
  volumeName: postgres-pv

Answer 2

您正在使用kubedb.com/v1alpha1的自定义Postgres-resource。

它们定义了一种处理storage的自定义方法。似乎你必须设置 spec.storage.storageClassName-key，因为

“没有storageClassName的聚氯乙烯是不完全相同的，集群会根据DefaultStorageClass准入插件是否打开而采取不同的处理方式。”

现在选择哪个StorageClass？

既然你在使用Minikube，我建议你坚持使用Minikube的minikube-hostpath。您可以查看它是否可用：

$ kubectl get storageclass
NAME                 PROVISIONER                AGE
standard (default)   k8s.io/minikube-hostpath   2m36s

支持dynamic provisioning，设置为默认StorageClass。

尝试设置spec.storage.storageClassName: minikube-hostpath并相应地更新您的卷。

Answer 3

实际上不可能做到你想要做的事情。

Kubedb的所有兴趣都是为了轻松构建数据库集群，这意味着每个实例都有专用的卷。Kubedb的操作员按需创建卷(PVC)，并将它们绑定到创建的pods。

您正在为动态CRD定义堆栈卷，因此它无法工作。

另外，操作员不会将volumeMounts传递给StatefulSet (由于上述原因)。

为了实现您的场景，您必须自己编写StatefulSet。