kubernetes 数据持久化 使用ceph存储-cephfs

PersistentVolume持久化卷(即PV)是Kubernetes对存储的抽象，PV可以是网络存储，不属于任何Node，但可以在每个Node上访问。PV有以下三种访问模式(Access Mode)：

• ReadWriteOnce：只可被一个Node挂载，这个Node对PV拥有读写权限
• ReadOnlyMany: 可以被多个Node挂载，这些Node对PV只有只读权限
• ReadWriteMany: 可以被多个Node挂载，这些Node对PV拥有读写权限

我们之前使用Ceph RBD作为Kubernetes集群的PV，在使用场景上基于Kubernetes的Dynamic Storage Provision特性，使用provisioner: kubernetes.io/rbd的StorageClass来动态创建PV并由volumeClaimTemplates中声明自动创建的PVC去绑定，当前这种形式很稳定的支撑了我们业务的需求。 但RBD的访问模式是ReadWriteOnce的，面对最近的ReadWriteMany的需求 各种存储文件系统的对比如下：

Volume Plugin	ReadWriteOnce	ReadOnlyMany	ReadWriteMany
AWSElasticBlockStore	✓	-	-
AzureFile	✓	✓	-
AzureDisk	✓	-	-
CephFS	✓	✓	✓
Cinder	✓	-	-
FC	✓	✓	-
FlexVolume	✓	✓	-
Flocker	✓	-	-
GCEPersistentDisk	✓	✓	-
Glusterfs	✓	✓	✓
HostPath	✓	-	-
iSCSI	✓	✓	-
PhotonPersistentDisk	✓	-	-
Quobyte	✓	✓	✓
NFS	✓	✓	✓
RBD	✓	✓	-
VsphereVolume	✓	-	-(works when pods are collocated)
PortworxVolume	✓	-	✓
ScaleIO	✓	✓	-
StorageOS	✓	-	-

如果使用 ReadWriteMany, 通过上面的对比，cephfs 是最佳的选择！

CephFS方式支持k8s的pv的3种访问模式:

                 ReadWriteOnce，

                 ReadOnlyMany ，

                 ReadWriteMany

一: 首先Ceph端创建CephFS pool

 

二: 部署 配置 storageclass

创建系统级 Secret	# ceph auth get-key client.admin|more AQAYz3lekwIKKxAA+HUR4UIIK2GrljL5k7sYbg== # kubectl create secret generic cephfs-secret --type="kubernetes.io/rbd" --from-literal=key=AQAYz3lekwIKKxAA+HUR4UIIK2GrljL5k7sYbg==  --namespace=default secret/cephfs-secret created #
查看 secret	#kubectl get secret cephfs-secret  -o yaml
配置 StorageClass	cat >storageclass-cephfs.yaml< kind: StorageClass apiVersion: storage.k8s.io/v1 metadata: name: dynamic-cephfs provisioner: ceph.com/cephfs parameters:    monitors: 100.100.100.100:6789,100.100.100.101:6789,100.100.100.102:6789    adminId: admin    adminSecretName: cephfs-screct    adminSecretNamespace: "default"    claimRoot: /volumes/kubernetes EOF
创建	# kubectl apply -f storageclass-cephfs.yaml storageclass.storage.k8s.io/dynamic-cephfs created
查看	# kubectl get sc|grep cephfs dynamic-cephfs        ceph.com/cephfs   7s

三: 测试使用

创建pvc测试	# cat cephfs-pvc-test.yaml   kind: PersistentVolumeClaim apiVersion: v1 metadata:   name: cephfs-claim spec:   accessModes:         - ReadWriteMany   storageClassName: dynamic-cephfs   resources:     requests:       storage: 2Gi   # kubectl apply -f cephfs-pvc-test.yaml persistentvolumeclaim/cephfs-claim created #
查看	# kubectl get pvc NAME      STATUS   VOLUME        CAPACITY   ACCESS MODES                                              STORAGECLASS          AGE cephfs-claim     Bound    pvc-e30e1c1f-fa5b-4bd3-8d9a-0f5f98f9fb95   2Gi        RWX       dynamic-cephfs        43s     # kubectl get pv NAME    CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM    STORAGECLASS          REASON   AGE pvc-e30e1c1f-fa5b-4bd3-8d9a-0f5f98f9fb95   2Gi        RWX            Delete           Bound       default/cephfs-claim                       dynamic-cephfs                 2m21s
创建 nginx pod 挂载测试	# cat cephfs-deployment.yaml kind: Deployment apiVersion: apps/v1 metadata:   labels:     app: cephfs-nginx-pod   name: cephfs-nginx-pod   namespace: default spec:   replicas: 1   selector:     matchLabels:       app: cephfs-nginx-pod   template:     metadata:       labels:         app: cephfs-nginx-pod     spec:       containers:       - name: cephfs-nginx-pod         image: nginx         imagePullPolicy: Always         resources:           requests:             memory: "1Gi"             cpu: "250m"           limits:             memory: "1Gi"             cpu: "500m"         volumeMounts:           - name: cephfs             mountPath: "/usr/share/nginx/html"         ports:           - containerPort: 80             protocol: TCP       volumes:         - name: cephfs           persistentVolumeClaim:             claimName: cephfs-claim # #
查看	# kubectl apply -f cephfs-deployment.yaml deployment.apps/cephfs-nginx-pod created # kubectl get deployment|grep cephfs cephfs-nginx-pod         0/1     1            0           9s # kubectl get pod|grep cephfs cephfs-nginx-pod-7569d79f87-5jsc7         0/1     ContainerCreating   0          15s # kubectl get pod|grep cephfs cephfs-nginx-pod-7569d79f87-5jsc7         1/1     Running             0          43s # kubectl get pod -o wide|grep cephfs cephfs-nginx-pod-7569d79f87-5jsc7         1/1     Running             0          87s     10.244.1.48   node-17              # #
创建service	# cat cephfs-service.yaml apiVersion: v1 kind: Service metadata:   name: cephfs-service spec:   type: NodePort   ports:    - protocol: TCP      port: 80      targetPort: 80   selector:     app: cephfs-nginx-pod   # kubectl apply -f cephfs-service.yaml service/cephfs-service created # kubectl get svc|grep cephfs cephfs-service        NodePort    10.0.0.163           80:31214/TCP   24s #
创建ingress	# cat cephfs-ingress.yaml apiVersion: v1 kind: List items: - apiVersion: extensions/v1beta1   kind: Ingress   metadata:     name: cephfs-ingress     namespace: default     annotations:       nginx.ingress.kubernetes.io/rewrite-target: /   spec:     rules:     - host: 04.test.cn       http:         paths:         - path: /           backend:             serviceName: cephfs-service             servicePort: 80   #   # kubectl apply -f cephfs-ingress.yaml ingress.extensions/cephfs-ingress created # # kubectl get ingress NAME                  HOSTS          ADDRESS   PORTS   AGE   cephfs-ingress        04.test.cn             80      15m   # kubectl get ep|grep cephfs cephfs-service        10.244.1.48:80                  23m #
域名访问	http://04.test.cn