我们在使用kubernetes/docker时最重要的是要对数据做持久化，ceph做为一个开源的分布式存储系统，支持对象存储，块存储rbd，文件系cephfs，同时具备高可靠，易扩展等特性，kubernetes+ceph在很多企业已经落地实施，也是目前最成熟可靠的方案，本篇博客主要为大家讲解基于storageclass动态管理存储的整个生命周期。
1.创建kubernetes对接ceph需要的外部客户端rbd-provisioner
注：假如你的kubernetes集群是由kubeadm初始化时，那么kube-controller-manager本身是没有rbd的命令，所以需要添加一个外部插件
quay.io/external_storage/rbd-provisioner:latest，添加方法如下
cat rbd-provisioner.yaml
kind: ClusterRole apiVersion: rbac.authorization.k8s.io/v1 metadata: name: rbd-provisioner 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: ["create", "update", "patch"] - apiGroups: [""] resources: ["services"] resourceNames: ["kube-dns","coredns"] verbs: ["list", "get"] --- kind: ClusterRoleBinding apiVersion: rbac.authorization.k8s.io/v1 metadata: name: rbd-provisioner subjects: - kind: ServiceAccount name: rbd-provisioner namespace: default roleRef: kind: ClusterRole name: rbd-provisioner apiGroup: rbac.authorization.k8s.io --- apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: name: rbd-provisioner rules: - apiGroups: [""] resources: ["secrets"] verbs: ["get"] - apiGroups: [""] resources: ["endpoints"] verbs: ["get", "list", "watch", "create", "update", "patch"] --- apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: name: rbd-provisioner roleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: rbd-provisioner subjects: - kind: ServiceAccount name: rbd-provisioner namespace: default --- apiVersion: extensions/v1beta1 kind: Deployment metadata: name: rbd-provisioner spec: replicas: 1 strategy: type: Recreate template: metadata: labels: app: rbd-provisioner spec: containers: - name: rbd-provisioner image: quay.io/external_storage/rbd-provisioner:latest env: - name: PROVISIONER_NAME value: ceph.com/rbd serviceAccount: rbd-provisioner --- apiVersion: v1 kind: ServiceAccount metadata: name: rbd-provisione
kubectl apply -f rbd-provisioner.yaml
2.创建ceph-secret这个k8s的secret对象，这个secret对象用于k8s volume插件访问ceph集群用的
（1）在ceph集群的管理节点获取client.admin的keyring值，并用base64编码，在ceph集群的管理节点上操作
ceph auth get-key client.admin | base64
获取的结果如下所示
QVFBczlGOWRCVTkrSXhBQThLa1k4VERQQjhVT29wd0FnZkNDQmc9PQ==
（2）创建secret
cat ceph-secret.yaml
apiVersion: v1 kind: Secret metadata: name: ceph-secret type: "ceph.com/rbd" data: key: QVFBczlGOWRCVTkrSXhBQThLa1k4VERQQjhVT29wd0FnZkNDQmc9PQ==
kubectl apply -f ceph-secret.yaml
3.创建storageclass
（1）在ceph集群的管理节点创建pool池
ceph osd pool create k8stest 256
rbd create rbda -s 1024 -p k8stest
rbd feature disable k8stest/rbda object-map fast-diff deep-flatten
（2）在k8s集群的master节点创建storageclass
cat storageclass.yaml
apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: k8s-rbd provisioner: ceph.com/rbd parameters: monitors: 192.168.199.201:6789 adminId: admin adminSecretName: ceph-secret pool: k8stest userId: admin userSecretName: ceph-secret fsType: xfs imageFormat: "2" imageFeatures: "layering"
注：storageclass参数说明
monitors: 192.168.199.201:6789 #ceph集群的监控节点，如果monitor是多个，可以写多个monitor地址，用,分割 pool: k8stest #pool池，需要事先创建，在ceph集群的管理节点，按照上面创建pool的步骤创建即可 userId: admin #k8s访问ceph集群使用admin管理用户 userSecretName: ceph-secret #k8s访问ceph需要的密钥，就是我们上面创建的secret fsType: xfs #rbd块的文件系统类型，可以是xfs，也可以是ext4 imageFormat: "2" #默认即可 imageFeatures: "layering" #默认即可
kubectl apply -f storageclass.yaml
4.statefulset+ceph最佳实践测试
cat stat.yaml
apiVersion: v1 kind: Service metadata: name: storage labels: app: storage spec: ports: - port: 80 name: web clusterIP: None selector: app: storage --- apiVersion: apps/v1beta1 kind: StatefulSet metadata: name: storage spec: serviceName: "storage" replicas: 2 template: metadata: labels: app: storage 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" ] volumeMode: Filesystem storageClassName: k8s-rbd resources: requests: storage: 1Gi
kubectl apply -f state.yaml
上面命令执行之后，会自动生成pvc，pv，然后把pvc和pv绑定
上面的pv是通过storageclass这个存储类动态生成的
