[kubernetes]10-4 共享存储 --- PV、PVC和StorageClass（上）

 

10-4 共享存储 --- PV、PVC和StorageClass（上）

 

pv 描述的是持久化数据卷

nfs 类型的挂载目录

apiVersion: v1
kind: PersistentVolume
metadata:
  name: nfs
spec:
  capacity:
    storage: 10Gi
# 表示只有一个pod可以读写访问这个pv  ReadWriteAny的话表示都可以访问
  accessModes:
    - ReadWriteOnce
  nfs:
    path: "/tmp"
    server: 172.22.1.2

 

pvc 描述pod希望使用的持久化存储的属性

 

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
   name: nfs
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi
      

 

pv和pvc必需要建立绑定关系才行

绑定的过程1 首先两者必须匹配 pv需要满足pvc的需求 2 pv和pvc的storageclass name必须一致

两者满足之后 processtermvolume controller 会发现这个匹配的pv，然后自动将pv和pvc建立绑定关系。本质上是在pvc的资源描述对象里把pv的名字加进去。

 

 

当pv和pvc绑定好之后

创建pod

apiVersion: v1
kind: Pod
metadata:
  name: web-dev
spec: 
  containers:
  - name: web-dev
    images: web:v1
    ports:
    - containerPort: 8080
    volumeMounts:
    - name: nfs
      mountPath: "/files"
  volumes:
  - name: nfs
    persistentVolumeClaim:
      claimName: nfs     

 

nfs：kubelet会把目录远程挂在到pv指定的位置，相当于mount命令。挂载好之后对于docker来说并没有什么区别，依旧是使用docker run -v 参数把目录映射到容器里

 

 

 

StorageClass

自动管理pv的机制 本质是pv的模板

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: storage-class-demo
  # 内置的存储插件
provisioner: kubernetes.io/aws-ebs
# aws-ebs的具体参数  需要根据插件修改
parameters:
  type: io1
  zone: us-east-1d
  iopsPerGB: "10"

 

 

有了StorageClass后的pvc 如下

会根据storageclassname的值 自动去创建pv 并建立绑定关系

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-demo
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: storage-class-demo
  resources:
    requests:
      storage: 10Gi

 

StorageClass的设计要点

1 每个PV和PVC都有StorageClass 如果没有创建那就会默认一个空的

2 StorageClass 不需要真实存在 名字一样就行

 

 

 

gluster-fs

3个节点 每个节点上 需要一个裸磁盘

 

3个节点先按照之前的步骤 座位node 加入kubernetes 并且添加好/etc/hosts

 

3个节点均执行

yum -y install glusterfs glusterfs-fuse

 

安装完成之后 master上可以grep到一个allow-privileged的api

 

 

 

glusterfs-daemonset.yaml 

---
kind: DaemonSet
apiVersion: extensions/v1beta1
metadata:
  name: glusterfs
  labels:
    glusterfs: daemonset
  annotations:
    description: GlusterFS DaemonSet
    tags: glusterfs
spec:
  template:
    metadata:
      name: glusterfs
      labels:
        glusterfs: pod
        glusterfs-node: pod
    spec:
      nodeSelector:
        storagenode: glusterfs
      hostNetwork: true
      containers:
      - image: gluster/gluster-centos:latest
        imagePullPolicy: IfNotPresent
        name: glusterfs
        env:
        # alternative for /dev volumeMount to enable access to *all* devices
        - name: HOST_DEV_DIR
          value: "/mnt/host-dev"
        # set GLUSTER_BLOCKD_STATUS_PROBE_ENABLE to "1" so the
        # readiness/liveness probe validate gluster-blockd as well
        - name: GLUSTER_BLOCKD_STATUS_PROBE_ENABLE
          value: "1"
        - name: GB_GLFS_LRU_COUNT
          value: "15"
        - name: TCMU_LOGDIR
          value: "/var/log/glusterfs/gluster-block"
        resources:
          requests:
            memory: 100Mi
            cpu: 100m
        volumeMounts:
        - name: glusterfs-heketi
          mountPath: "/var/lib/heketi"
        - name: glusterfs-run
          mountPath: "/run"
        - name: glusterfs-lvm
          mountPath: "/run/lvm"
        - name: glusterfs-etc
          mountPath: "/etc/glusterfs"
        - name: glusterfs-logs
          mountPath: "/var/log/glusterfs"
        - name: glusterfs-config
          mountPath: "/var/lib/glusterd"
        - name: glusterfs-host-dev
          mountPath: "/mnt/host-dev"
        - name: glusterfs-misc
          mountPath: "/var/lib/misc/glusterfsd"
        - name: glusterfs-block-sys-class
          mountPath: "/sys/class"
        - name: glusterfs-block-sys-module
          mountPath: "/sys/module"
        - name: glusterfs-cgroup
          mountPath: "/sys/fs/cgroup"
          readOnly: true
        - name: glusterfs-ssl
          mountPath: "/etc/ssl"
          readOnly: true
        - name: kernel-modules
          mountPath: "/usr/lib/modules"
          readOnly: true
        securityContext:
          capabilities: {}
          privileged: true
        readinessProbe:
          timeoutSeconds: 3
          initialDelaySeconds: 40
          exec:
            command:
            - "/bin/bash"
            - "-c"
            - "if command -v /usr/local/bin/status-probe.sh; then /usr/local/bin/status-probe.sh readiness; else systemctl status glusterd.service; fi"
          periodSeconds: 25
          successThreshold: 1
          failureThreshold: 50
        livenessProbe:
          timeoutSeconds: 3
          initialDelaySeconds: 40
          exec:
            command:
            - "/bin/bash"
            - "-c"
            - "if command -v /usr/local/bin/status-probe.sh; then /usr/local/bin/status-probe.sh liveness; else systemctl status glusterd.service; fi"
          periodSeconds: 25
          successThreshold: 1
          failureThreshold: 50
      volumes:
      - name: glusterfs-heketi
        hostPath:
          path: "/var/lib/heketi"
      - name: glusterfs-run
      - name: glusterfs-lvm
        hostPath:
          path: "/run/lvm"
      - name: glusterfs-etc
        hostPath:
          path: "/etc/glusterfs"
      - name: glusterfs-logs
        hostPath:
          path: "/var/log/glusterfs"
      - name: glusterfs-config
        hostPath:
          path: "/var/lib/glusterd"
      - name: glusterfs-host-dev
        hostPath:
          path: "/dev"
      - name: glusterfs-misc
        hostPath:
          path: "/var/lib/misc/glusterfsd"
      - name: glusterfs-block-sys-class
        hostPath:
          path: "/sys/class"
      - name: glusterfs-block-sys-module
        hostPath:
          path: "/sys/module"
      - name: glusterfs-cgroup
        hostPath:
          path: "/sys/fs/cgroup"
      - name: glusterfs-ssl
        hostPath:
          path: "/etc/ssl"
      - name: kernel-modules
        hostPath:
          path: "/usr/lib/modules"