k8s-静态PV和动态PV

1、pv 简单介绍

PersistenVolume（PV）：对存储资源创建和使用的抽象，使得存储作为集群中的资源管理 PV分为静态和动态，动态能够自动创建PV • PersistentVolumeClaim（PVC）：让用户不需要关心具体的Volume实现细节容器与PV、PVC之间的关系，可以如下图所示：总的来说，PV是提供者，PVC是消费者，消费的过程就是绑定。参考网址：1、https://www.cnblogs.com/weifeng1463/p/10037803.html 2、https://blog.csdn.net/qq_25611295/article/details/86065053

2、nfs 搭建：

yum install nfs-utils
   
vim /etc/exports
/data/k8s/ 172.16.1.0/24(sync,rw,no_root_squash)
   
systemctl start nfs;  systemctl start rpcbind  
systemctl enable nfs
 
测试：
yum install nfs-utils
showmount -e 172.16.1.131

3、PersistentVolume 静态绑定（手工创建PV、PVC）

[root@VM_0_48_centos prometheus]# cat mypv.yaml 
apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv001
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteMany
  nfs:
    path: /data/k8s
    server: 172.19.0.14

[root@VM_0_48_centos prometheus]# cat mypvc.yaml   ###会根据大小和类型自动匹配到上面的PV
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  namespace: kube-system
  name: prometheus-claim
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 10Gi

[root@VM_0_48_centos prometheus]# kubectl  get pv,pvc -n kube-system
NAME                     CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                          STORAGECLASS   REASON   AGE
persistentvolume/pv001   10Gi       RWX            Retain           Bound    kube-system/prometheus-claim                           17m

NAME                                     STATUS   VOLUME   CAPACITY   ACCESS MODES   STORAGECLASS   AGE
persistentvolumeclaim/prometheus-claim   Bound    pv001    10Gi       RWX

4、PersistentVolume 静态PVC使用案例

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apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: prometheus
  namespace: kube-system
  labels:
    k8s-app: prometheus
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
    version: v2.2.1
spec:
  serviceName: "prometheus"
  replicas: 1
  podManagementPolicy: "Parallel"
  updateStrategy:
   type: "RollingUpdate"
  selector:
    matchLabels:
      k8s-app: prometheus
  template:
    metadata:
      labels:
        k8s-app: prometheus
      annotations:
        scheduler.alpha.kubernetes.io/critical-pod: ''
    spec:
      priorityClassName: system-cluster-critical
      serviceAccountName: prometheus
      initContainers:
      - name: "init-chown-data"
        image: "busybox:latest"
        imagePullPolicy: "IfNotPresent"
        command: ["chown", "-R", "65534:65534", "/data"]
        volumeMounts:
        - name: prometheus-data
          mountPath: /data
          subPath: ""
      containers:
        - name: prometheus-server-configmap-reload
          image: "jimmidyson/configmap-reload:v0.1"
          imagePullPolicy: "IfNotPresent"
          args:
            - --volume-dir=/etc/config
            - --webhook-url=http://localhost:9090/-/reload
          volumeMounts:
            - name: config-volume
              mountPath: /etc/config
              readOnly: true
          resources:
            limits:
              cpu: 10m
              memory: 10Mi
            requests:
              cpu: 10m
              memory: 10Mi
 
        - name: prometheus-server
          image: "prom/prometheus:v2.2.1"
          imagePullPolicy: "IfNotPresent"
          args:
            - --config.file=/etc/config/prometheus.yml
            - --storage.tsdb.path=/data
            - --web.console.libraries=/etc/prometheus/console_libraries
            - --web.console.templates=/etc/prometheus/consoles
            - --web.enable-lifecycle
          ports:
            - containerPort: 9090
          readinessProbe:
            httpGet:
              path: /-/ready
              port: 9090
            initialDelaySeconds: 30
            timeoutSeconds: 30
          livenessProbe:
            httpGet:
              path: /-/healthy
              port: 9090
            initialDelaySeconds: 30
            timeoutSeconds: 30
          # based on 10 running nodes with 30 pods each
          resources:
            limits:
              cpu: 200m
              memory: 1000Mi
            requests:
              cpu: 200m
              memory: 1000Mi
 
          volumeMounts:
            - name: config-volume
              mountPath: /etc/config
            - name: prometheus-data
              mountPath: /data
              subPath: ""
      terminationGracePeriodSeconds: 300
      volumes:
        - name: config-volume
          configMap:
            name: prometheus-config
        - name: prometheus-data
          persistentVolumeClaim:   #申明使用静态PVC永久化存储
            claimName: prometheus-claim  

5、动态PV，K8S调用资源对象自动创建PV。生产环境常用

当我们k8s业务上来的时候，大量的pvc,此时我们人工创建匹配的话，工作量就会非常大了，需要动态的自动挂载相应的存储。

我们需要使用到StorageClass，来对接存储，靠他来自动关联pvc,并创建pv。 Kubernetes支持动态供给的存储插件： https://kubernetes.io/docs/concepts/storage/storage-classes/ 因为NFS不支持动态存储，所以我们需要借用这个存储插件。 nfs动态相关部署可以参考： https://github.com/kubernetes-incubator/external-storage/tree/master/nfs-client/deploy

6、存储对象申明和授权。

定义一个storage
[root@VM_0_48_centos prometheus]# cat  storageclass-nfs.yaml 
apiVersion: storage.k8s.io/v1beta1
kind: StorageClass
metadata:
  name: managed-nfs-storage
provisioner: fuseim.pri/ifs

因为storage自动创建pv需要经过kube-apiserver,所以要进行授权
[root@VM_0_48_centos prometheus]# cat    storageclass-rbac.yaml
apiVersion: v1
kind: ServiceAccount
metadata:
  name: nfs-client-provisioner

---

kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: nfs-client-provisioner-runner
rules:
  - apiGroups: [""]
    resources: ["persistentvolumes"]
    verbs: ["get", "list", "watch", "create", "delete"]
  - apiGroups: [""]
    resources: ["persistentvolumeclaims"]
    verbs: ["get", "list", "watch", "update"]
  - apiGroups: ["storage.k8s.io"]
    resources: ["storageclasses"]
    verbs: ["get", "list", "watch"]
  - apiGroups: [""]
    resources: ["events"]
    verbs: ["list", "watch", "create", "update", "patch"]

---

kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: run-nfs-client-provisioner
subjects:
  - kind: ServiceAccount
    name: nfs-client-provisioner
    namespace: default
roleRef:
  kind: ClusterRole
  name: nfs-client-provisioner-runner
  apiGroup: rbac.authorization.k8s.io

部署一个自动创建pv的服务
[root@VM_0_48_centos prometheus]# cat prometheus-statefulset.yaml 
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: prometheus
  namespace: kube-system
  labels:
    k8s-app: prometheus
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
    version: v2.2.1
spec:
  serviceName: "prometheus"
  replicas: 1
  podManagementPolicy: "Parallel"
  updateStrategy:
   type: "RollingUpdate"
  selector:
    matchLabels:
      k8s-app: prometheus
  template:
    metadata:
      labels:
        k8s-app: prometheus
      annotations:
        scheduler.alpha.kubernetes.io/critical-pod: ''
    spec:
      priorityClassName: system-cluster-critical
      serviceAccountName: prometheus
      initContainers:
      - name: "init-chown-data"
        image: "busybox:latest"
        imagePullPolicy: "IfNotPresent"
        command: ["chown", "-R", "65534:65534", "/data"]
        volumeMounts:
        - name: prometheus-data
          mountPath: /data
          subPath: ""
      containers:
        - name: prometheus-server-configmap-reload
          image: "jimmidyson/configmap-reload:v0.1"
          imagePullPolicy: "IfNotPresent"
          args:
            - --volume-dir=/etc/config
            - --webhook-url=http://localhost:9090/-/reload
          volumeMounts:
            - name: config-volume
              mountPath: /etc/config
              readOnly: true
          resources:
            limits:
              cpu: 10m
              memory: 10Mi
            requests:
              cpu: 10m
              memory: 10Mi

        - name: prometheus-server
          image: "prom/prometheus:v2.2.1"
          imagePullPolicy: "IfNotPresent"
          args:
            - --config.file=/etc/config/prometheus.yml
            - --storage.tsdb.path=/data
            - --web.console.libraries=/etc/prometheus/console_libraries
            - --web.console.templates=/etc/prometheus/consoles
            - --web.enable-lifecycle
          ports:
            - containerPort: 9090
          readinessProbe:
            httpGet:
              path: /-/ready
              port: 9090
            initialDelaySeconds: 30
            timeoutSeconds: 30
          livenessProbe:
            httpGet:
              path: /-/healthy
              port: 9090
            initialDelaySeconds: 30
            timeoutSeconds: 30
          # based on 10 running nodes with 30 pods each
          resources:
            limits:
              cpu: 200m
              memory: 1000Mi
            requests:
              cpu: 200m
              memory: 1000Mi

          volumeMounts:
            - name: config-volume
              mountPath: /etc/config
            - name: prometheus-data
              mountPath: /data
              subPath: ""
      terminationGracePeriodSeconds: 300
      volumes:
        - name: config-volume
          configMap:
            name: prometheus-config
        - name: prometheus-data
          persistentVolumeClaim:
            claimName: prometheus-claim

7、效果测试

[root@VM_0_48_centos prometheus]# cat test.yaml 
apiVersion: v1
kind: Service
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    name: web
  clusterIP: None
  selector:
    app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  serviceName: "nginx"
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80
          name: web
        volumeMounts:
        - name: www
          mountPath: /usr/share/nginx/html
  volumeClaimTemplates:
  - metadata:
      name: www
    spec:
      accessModes: [ "ReadWriteOnce" ]
      storageClassName: "managed-nfs-storage"
      resources:
        requests:
          storage: 1Gi

kubectl exec -it web-0 sh
# cd /usr/share/nginx/html
# touch 1.txt