ceph提供底层存储功能 , cephfs方式支持k8s的pv的3种访问模式ReadWriteOnce , ReadOnlyMany , ReadWriteMany , RBD支持ReadWriteOnce , ReadOnlyMany两种模式

动态供给主要是能够自动帮你创建pv , 需要多大的空间就创建多大的pv。k8s帮助创建pv , 创建pvc就直接api调用存储类来寻找pv。

如果是存储静态供给的话 , 会需要我们手动去创建pv , 如果没有足够的资源 , 找不到合适的pv , 那么pod就会处于pending等待的状态。而动态供给主要的一个实现就是StorageClass存储对象 , 其实它就是声明你使用哪个存储 , 然后帮你去连接 , 再帮你去自动创建pv。

1. 使用Ceph RBD作为持久数据卷

1.1 配置 rbd-provisioner

编写yaml文件

[root@k8s-master ~]# cat >external-storage-rbd-provisioner.yaml<<EOF
apiVersion: v1
kind: ServiceAccount
metadata:
  name: rbd-provisioner
  namespace: kube-system
---
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: ["endpoints"]
    verbs: ["get", "list", "watch", "create", "update", "patch"]
  - apiGroups: [""]
    resources: ["services"]
    resourceNames: ["kube-dns"]
    verbs: ["list", "get"]
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: rbd-provisioner
subjects:
  - kind: ServiceAccount
    name: rbd-provisioner
    namespace: kube-system
roleRef:
  kind: ClusterRole
  name: rbd-provisioner
  apiGroup: rbac.authorization.k8s.io

---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: rbd-provisioner
  namespace: kube-system
rules:
- apiGroups: [""]
  resources: ["secrets"]
  verbs: ["get"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: rbd-provisioner
  namespace: kube-system
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: rbd-provisioner
subjects:
- kind: ServiceAccount
  name: rbd-provisioner
  namespace: kube-system
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: rbd-provisioner
  namespace: kube-system
spec:
  selector:
    matchLabels:
      app: rbd-provisioner
  replicas: 1
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: rbd-provisioner
    spec:
      containers:
      - name: rbd-provisioner
        image: "registry.cn-chengdu.aliyuncs.com/ives/rbd-provisioner:v2.0.0-k8s1.11"
        env:
        - name: PROVISIONER_NAME
          value: ceph.com/rbd
      serviceAccount: rbd-provisioner
EOF

创建相关资源

[root@k8s-master ~]# kubectl apply -f external-storage-rbd-provisioner.yaml

[root@k8s-master ~]# kubectl get pods -n kube-system  |grep rbd
rbd-provisioner-7c77dcfd67-9xv2m     1/1     Running   0          59s

1.2. 配置 storageclass

创建pod时 , kubelet需要使用rbd命令去检测和挂载pv对应的ceph image , 所以要在所有k8s的worker节点安装ceph客户端ceph-common。将ceph的ceph.client.admin.keyring和ceph.conf文件拷贝到master的/etc/ceph目录下。

安装ceph-common(k8s所有工作节点)
```
# yum -y install ceph-common
```

创建 osd pool , 在ceph的mon或者admin节点

[root@ceph_node1 ~]# ceph osd pool create kube 8
pool 'kube' created

[root@ceph_node1 ~]# ceph osd pool ls 
kube

创建k8s访问ceph的用户 , 在ceph的mon或者admin节点

[root@ceph_node1 ~]# ceph auth get-or-create client.kube mon 'allow r' osd 'allow class-read object_prefix rbd_children, allow rwx pool=kube' -o ceph.client.kube.keyring

查看key , 在ceph的mon或者admin节点

[root@ceph_node1 ~]# ceph auth get-key client.admin
AQCzcPFeYnOoABAATaM1Wt8tMgvYTQjj6YEuVg==

[root@ceph_node1 ~]# ceph auth get-key client.kube
AQC5+vJehk7XIRAAr9mtGFHlUSfT7yQMANeWaw==

创建admin secret , 在k8s管理节点

#CEPH_ADMIN_SECRET替换为 client.admin 获取到的key
[root@k8s-master ~]# export CEPH_ADMIN_SECRET='AQCzcPFeYnOoABAATaM1Wt8tMgvYTQjj6YEuVg=='

[root@k8s-master ~]# kubectl create secret generic ceph-secret --type="kubernetes.io/rbd" \
--from-literal=key=$CEPH_ADMIN_SECRET \
--namespace=kube-system

在default命名空间创建pvc用于访问ceph 的secret , 在k8s管理节点

#CEPH_KUBE_SECRET替换为 client.kube 获取到的key
[root@k8s-master ~]# export CEPH_KUBE_SECRET='AQC5+vJehk7XIRAAr9mtGFHlUSfT7yQMANeWaw=='

[root@k8s-master ~]# kubectl create secret generic ceph-user-secret --type="kubernetes.io/rbd" \
--from-literal=key=$CEPH_KUBE_SECRET \
--namespace=default

查看secret

[root@k8s-master ~]# kubectl get secret ceph-user-secret -o yaml
[root@k8s-master ~]# kubectl get secret ceph-secret -n kube-system -o yaml

配置StorageClass

[root@k8s-master ~]# cat >storageclass-ceph-rdb.yaml<<EOF
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: dynamic-ceph-rdb
provisioner: ceph.com/rbd
parameters:
  monitors: 192.168.3.27:6789,192.168.3.60:6789,192.168.3.95:6789
  adminId: admin
  adminSecretName: ceph-secret
  adminSecretNamespace: kube-system
  pool: kube
  userId: kube
  userSecretName: ceph-user-secret
  fsType: ext4
  imageFormat: "2"
  imageFeatures: "layering"
EOF

创建StorageClass

[root@k8s-master ~]# kubectl apply -f storageclass-ceph-rdb.yaml

查看
```
[root@k8s-master ~]# kubectl get sc
```

1.3 测试使用

创建pvc测试

[root@k8s-master ~]# cat >ceph-rdb-pvc-test.yaml<<EOF
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: ceph-rdb-claim
spec:
  accessModes:     
    - ReadWriteOnce
  storageClassName: dynamic-ceph-rdb
  resources:
    requests:
      storage: 2Gi
EOF

[root@k8s-master ~]# kubectl apply -f ceph-rdb-pvc-test.yaml 
persistentvolumeclaim/ceph-rdb-claim created

查看pvc和pv

[root@k8s-master ~]# kubectl get pvc 
NAME             STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS       AGE
ceph-rdb-claim   Bound    pvc-bd2363f1-a841-46d0-ad54-99267173bc04   2Gi        RWO            dynamic-ceph-rdb   16s

[root@k8s-master ~]# kubectl get pv
NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM                    STORAGECLASS       REASON   AGE
pvc-bd2363f1-a841-46d0-ad54-99267173bc04   2Gi        RWO            Delete           Bound       default/ceph-rdb-claim   dynamic-ceph-rdb            29s

编写nginx pod资源配置清单进行测试

[root@k8s-master ~]# cat >nginx-pod.yaml<<EOF
apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod1
  labels:
    name: nginx-pod1
spec:
  containers:
  - name: nginx-pod1
    image: nginx:alpine
    ports:
    - name: web
      containerPort: 80
    volumeMounts:
    - name: ceph-rdb
      mountPath: /usr/share/nginx/html
  volumes:
  - name: ceph-rdb
    persistentVolumeClaim:
      claimName: ceph-rdb-claim
EOF

创建pod 并查看

[root@k8s-master ~]# kubectl apply -f nginx-pod.yaml 
pod/nginx-pod1 created

[root@k8s-master ~]# kubectl get pods 
NAME         READY   STATUS    RESTARTS   AGE
nginx-pod1   1/1     Running   0          2m25s

[root@k8s-master ~]# kubectl get pods -o wide 
NAME         READY   STATUS    RESTARTS   AGE     IP           NODE        NOMINATED NODE   READINESS GATES
nginx-pod1   1/1     Running   0          2m34s   10.244.1.5   k8s-node1   <none>           <none>

修改文件内容

[root@k8s-master ~]# kubectl exec -it nginx-pod1 -- /bin/sh -c 'echo Hello World from Ceph RBD!!! > /usr/share/nginx/html/index.html'

访问测试

[root@k8s-master ~]# POD_IP=$(kubectl get pods -o wide |grep nginx-pod1 |awk '{print $(NF-3)}')
[root@k8s-master ~]# curl $POD_IP
Hello World from Ceph RBD!!!

清理

[root@k8s-master ~]# kubectl delete -f nginx-pod.yaml 

[root@k8s-master ~]# kubectl delete -f ceph-rdb-pvc-test.yaml

2. 使用CephFS作为持久数据卷

2.1 Ceph端创建CephFS pool

创建两个pool分别存储数据和元数据 , 在ceph的mon或者admin节点 (这里测试 , 所以只给了8个pg_num)

[root@ceph_node1 ~]# ceph osd pool create fs_data 8
pool 'fs_data' created
[root@ceph_node1 ~]# ceph osd pool create fs_metadata 8
pool 'fs_metadata' created

创建一个CephFS , 在ceph的mon或者admin节点

[root@ceph_node1 ~]# ceph fs new cephfs fs_metadata fs_data
new fs with metadata pool 8 and data pool 7

查看

[root@ceph_node1 ~]# ceph fs ls 
name: cephfs, metadata pool: fs_metadata, data pools: [fs_data ]

2.2 配置 cephfs-provisioner

官方没有提供cephfs动态卷支持 , 使用社区提供的cephfs-provisioner