K8S学习笔记——创建pv

在K8S上使用存储的时候，需要创建Persistence Volumes（持久化卷）用于持久化数据，否则当pod重启后，数据将会丢失，可以参考官方文档：

https://kubernetes.io/zh-cn/docs/concepts/storage/persistent-volumes/

常用的持久卷类型有local（
 节点上挂载的本地存储设备），rbd（依赖Ceph，RBD 卷只能由单个使用者以读写模式安装。不允许同时写入），cephfs（依赖Ceph，同一 cephfs 卷可同时被多个写者挂载）等

https://kubernetes.io/zh-cn/docs/concepts/storage/volumes/

persistent volume，persistent volume claim和storage class的区别可以参考：Kubernetes对象之PersistentVolume，StorageClass和PersistentVolumeClaim

默认的storage class有HostPath，HostPath 卷 （仅供单节点测试使用；不适用于多节点集群； 请尝试使用 local 卷作为替代）

kubectl get sc -A
NAME                 PROVISIONER                RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
standard (default)   k8s.io/minikube-hostpath   Delete          Immediate           false                  40d

如果要创建一个local的storage class，首先需要编写一个local-storage.yaml

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

创建local sc

kubectl apply -f local-storage.yaml

查看创建的sc

kubectl get sc -A
NAME                 PROVISIONER                    RECLAIMPOLICY   VOLUMEBINDINGMODE      ALLOWVOLUMEEXPANSION   AGE
local-storage        kubernetes.io/no-provisioner   Retain          WaitForFirstConsumer   false                  2m41s
standard (default)   k8s.io/minikube-hostpath       Delete          Immediate              false                  41d

给local storage class下面增加一个kafka pv，kafka-local-pv.yaml

apiVersion: v1
kind: PersistentVolume
metadata:
  name: data-kafka-0
spec:
  capacity:
    storage: 5Gi
  accessModes:
  - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  storageClassName: local-storage
  local:
    path: /tmp/kafka/data-0
  nodeAffinity:
    required:
      nodeSelectorTerms:
      - matchExpressions:
        - key: kubernetes.io/hostname
          operator: In
          values:
          - minikube

创建kafka pv

kubectl apply -f kafka-local-pv.yaml

查看创建的kafka pv

kubectl get pv -A
NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM                              STORAGECLASS    REASON   AGE
data-kafka-0                               5Gi        RWO            Retain           Available                                      local-storage            6s

给local storage class下面增加一个zk pv，zookeeper-local-pv.yaml

apiVersion: v1
kind: PersistentVolume
metadata:
  name: data-zookeeper-0
spec:
  capacity:
    storage: 5Gi
  accessModes:
  - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  storageClassName: local-storage
  local:
    path: /tmp/zookeeper/data-0
  nodeAffinity:
    required:
      nodeSelectorTerms:
      - matchExpressions:
        - key: kubernetes.io/hostname
          operator: In
          values:
          - master

创建zookeeper pv

kubectl apply -f zookeeper-local-pv.yaml

查看创建的zookeeper pv

kubectl get pv,pvc --all-namespaces
NAME                                                        CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM                              STORAGECLASS    REASON   AGE
persistentvolume/data-kafka-0                               5Gi        RWO            Retain           Available                                      local-storage            12m
persistentvolume/data-zookeeper-0                           5Gi        RWO            Retain           Available                                      local-storage            2m5s