如何使用StorageClass挂载rbd？

使用StorageClass挂载ceph rbd需要用到2个cephx用户。一个用于创建和管理rbd，在这里我们使用admin；另一个用于将rbd映射到kubelet节点，我们可以在ceph中手动创建一个。

准备：

假设已有一套ceph集群，Monitor分别为192.168.1.1，192.168.1.2和192.168.1.3

需要保证Monitor的6379端口和OSD的6800端口对kubelet节点开放

为每个kubelet节点都事先安装ceph-common

一、创建一个k8s存储池，用于存放数据卷

ceph osd pool create k8s 64 64

二、创建cephx用户，用于映射rbd

ceph auth get-or-create client.k8s mon 'allow r' osd 'allow * pool=k8s'

三、获取k8s用户的key，以base64编码

ceph auth get-key client.k8s|base64

记录输出的内容，如：QVFEQjlmcFpjUE5lS0JBQU40NnZxZ2dIT0dRTEtaeUx1blNjR1E9PQ==

四、获取admin用户的key，以base64编码

ceph auth get-key client.admin|base64

记录输出的内容，如：QVFDUDNrQllRRVBJR0JBQXFuVXJQbHZQaC9xZEQ2ZGVZOXRoVXc9PQ==

五、创建storage-class-rbd.yaml

---
apiVersion: v1
data:
  key: QVFEQjlmcFpjUE5lS0JBQU40NnZxZ2dIT0dRTEtaeUx1blNjR1E9PQ==
kind: Secret
metadata:
  name: ceph-secret-user
  namespace: default
type: kubernetes.io/rbd
---
apiVersion: v1
data:
  key: QVFDUDNrQllRRVBJR0JBQXFuVXJQbHZQaC9xZEQ2ZGVZOXRoVXc9PQ==
kind: Secret
metadata:
  name: ceph-secret-admin
  namespace: kube-system
type: kubernetes.io/rbd
---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: rbd
provisioner: kubernetes.io/rbd
parameters:
  monitors: 192.168.1.1:6789,192.168.1.2:6789,192.168.1.3:6789
  adminId: admin
  adminSecretName: ceph-secret-admin
  adminSecretNamespace: kube-system
  pool: k8s
  userId: k8s
  userSecretName: ceph-secret-user
  fsType: xfs
  imageFormat: "2"
  imageFeatures: "layering"

六、创建StorageClass

kubectl create -f ./storage-class-rbd.yaml

七、创建nginx-statefulset.yaml, 通过StatefulSet动态挂载卷

---
apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
  name: web
spec:
  serviceName: "nginx"
  replicas: 2
  volumeClaimTemplates:
  - metadata:
      name: html 
      annotations:
        volume.beta.kubernetes.io/storage-class: "rbd" # 这里配置 上面创建的 storageclass 的名称
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 2Gi 
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        volumeMounts:
        - mountPath: "/usr/share/nginx/html/"
          name: html

StatefulSet会为每个Pod创建一个rbd数据卷，并挂载到/usr/share/nginx/html/目录中,数据卷会随着StatefulSet的伸缩而动态创建。