简介
ceph支持对象存储，文件系统及块存储，是三合一存储类型，kubernetes的样例中有cephfs与rbd两种使用方式的介绍，cephfs需要node节点安装ceph才能支持，rbd需要node节点安装ceph-common才支持。
使用上的区别如下：
Volume Plugin ReadWriteOnce ReadOnlyMany ReadWriteMany CephFS RBD -
基本环境
k81集群1.13.1版本
[root@elasticsearch01 ~]# kubectl get nodesNAME STATUS ROLES AGE VERSION10.2.8.34 Ready <none> 24d v1.13.110.2.8.65 Ready <none> 24d v1.13.1
ceph集群 luminous版本
[root@ceph01 ~]# ceph -s services: mon: 3 daemons, quorum ceph01,ceph02,ceph03 mgr: ceph03(active), standbys: ceph02, ceph01 osd: 24 osds: 24 up, 24 in rgw: 3 daemons active
操作步骤
一、ceph集群创建ceph池及镜像
[root@ceph01 ~]# ceph osd pool create rbd-k8s 1024 1024 For better initial performance on pools expected to store a large number of objects, consider supplying the expected_num_objects parameter when creating the pool. [root@ceph01 ~]# ceph osd lspools 1 rbd-es,2 .rgw.root,3 default.rgw.control,4 default.rgw.meta,5 default.rgw.log,6 default.rgw.buckets.index,7 default.rgw.buckets.data,8 default.rgw.buckets.non-ec,9 rbd-k8s, [root@ceph01 ~]# rbd create rbd-k8s/cephimage1 --size 10240[root@ceph01 ~]# rbd create rbd-k8s/cephimage2 --size 20480[root@ceph01 ~]# rbd create rbd-k8s/cephimage3 --size 40960[root@ceph01 ~]# rbd list rbd-k8scephimage1 cephimage2 cephimage3
二、k8s集群使用ceph rbd块存储
1、下载样例
[root@elasticsearch01 ~]# git clone https://github.com/kubernetes/examples.gitCloning into 'examples'... remote: Enumerating objects: 11475, done. remote: Total 11475 (delta 0), reused 0 (delta 0), pack-reused 11475 Receiving objects: 100% (11475/11475), 16.94 MiB | 6.00 MiB/s, done. Resolving deltas: 100% (6122/6122), done. [root@elasticsearch01 ~]# cd examples/staging/volumes/rbd[root@elasticsearch01 rbd]# lsrbd-with-secret.yaml rbd.yaml README.md secret [root@elasticsearch01 rbd]# cp -a ./rbd /k8s/yaml/volumes/
2、k8s集群节点安装ceph客户端
[root@elasticsearch01 ceph]# yum install ceph-common
3、修改rbd-with-secret.yaml配置文件
修改后配置如下：
[root@elasticsearch01 rbd]# cat rbd-with-secret.yaml apiVersion: v1kind: Podmetadata: name: rbd2spec: containers: - image: kubernetes/pause name: rbd-rw volumeMounts: - name: rbdpd mountPath: /mnt/rbd volumes: - name: rbdpd rbd: monitors: - '10.0.4.10:6789' - '10.0.4.13:6789' - '10.0.4.15:6789' pool: rbd-k8s image: cephimage1 fsType: ext4 readOnly: true user: admin secretRef: name: ceph-secret
如下参数根据实际情况修改：
monitors：这是 Ceph集群的monitor 监视器，Ceph 集群可以配置多个 monitor，本配置3个mon
pool：这是Ceph集群中存储数据进行归类区分使用，这里用的pool为rbd-ceph
image：这是Ceph 块设备中的磁盘映像文件，这里用的是cephimage1
fsType：文件系统类型，默认使用 ext4 即可
readOnly：是否为只读，这里测试使用只读即可
user：这是Ceph Client访问Ceph存储集群所使用的用户名，这里我们使用admin 即可
keyring：这是Ceph集群认证需要的密钥环，搭建Ceph存储集群时生成的ceph.client.admin.keyring
imageformat：这是磁盘映像文件格式，可以使用 2，或者老一些的1，内核版本比较低的使用1
imagefeatures： 这是磁盘映像文件的特征，需要uname -r查看集群系统内核所支持的特性，这里Ceontos7.4内核版本为3.10.0-693.el7.x86_64只支持layering
4、使用ceph认证秘钥
在集群中使用secret更方便易于扩展且安全
[root@ceph01 ~]# cat /etc/ceph/ceph.client.admin.keyring [client.admin]
key = AQBHVp9bPirBCRAAUt6Mjw5PUjiy/RDHyHZrUw==
[root@ceph01 ~]# grep key /etc/ceph/ceph.client.admin.keyring |awk '{printf "%s", $NF}'|base64QVFCSFZwOWJQaXJCQ1JBQVV0Nk1qdzVQVWppeS9SREh5SFpyVXc9PQ==5、创建ceph-secret
[root@elasticsearch01 rbd]# cat secret/ceph-secret.yaml apiVersion: v1kind: Secretmetadata: name: ceph-secrettype: "kubernetes.io/rbd"data: key: QVFCSFZwOWJQaXJCQ1JBQVV0Nk1qdzVQVWppeS9SREh5SFpyVXc9PQ== [root@elasticsearch01 rbd]# kubectl create -f secret/ceph-secret.yaml secret/ceph-secret created
6、创建pod测试rbd
按照官网的案例直接创建即可
[root@elasticsearch01 rbd]# kubectl create -frbd-with-secret.yaml
但是生产环境中不直接使用volumes，他会随着pods的创建儿创建，删除而删除，数据得不到保存，如果需要数据不丢失，需要借助pv和pvc实现
7、创建ceph-pv
注意rbd是读写一次，只读多次，目前还不支持读写多次，我们日常使用rbd映射磁盘时也是一个image只挂载一个客户端上；cephfs可以支持读写多次
[root@elasticsearch01 rbd]# cat rbd-pv.yaml apiVersion: v1kind: PersistentVolumemetadata: name: ceph-rbd-pvspec: capacity: storage: 20Gi accessModes: - ReadWriteOnce rbd: monitors: - '10.0.4.10:6789' - '10.0.4.13:6789' - '10.0.4.15:6789' pool: rbd-k8s image: cephimage2 user: admin secretRef: name: ceph-secret fsType: ext4 readOnly: false persistentVolumeReclaimPolicy: Recycle [root@elasticsearch01 rbd]# kubectl create -f rbd-pv.yaml persistentvolume/ceph-rbd-pv created [root@elasticsearch01 rbd]# kubectl get pvNAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE ceph-rbd-pv 20Gi RWO Recycle Available
8、创建ceph-pvc
[root@elasticsearch01 rbd]# cat rbd-pv-claim.yaml apiVersion: v1 kind: PersistentVolumeClaim metadata: name: ceph-rbd-pv-claim spec: accessModes: - ReadWriteOnce resources: requests: storage: 10Gi [root@elasticsearch01 rbd]# kubectl create -f rbd-pv-claim.yaml persistentvolumeclaim/ceph-rbd-pv-claim created [root@elasticsearch01 rbd]# kubectl get pvcNAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE ceph-rbd-pv-claim Bound ceph-rbd-pv 20Gi RWO 6s [root@elasticsearch01 rbd]# kubectl get pvNAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE ceph-rbd-pv 20Gi RWO Recycle Bound default/ceph-rbd-pv-claim 5m28s
9、创建pod通过pv、pvc方式测试rbd
由于需要格式化挂载rbd，rbd空间比较大10G，需要时间比较久，大概需要几分钟
[root@elasticsearch01 rbd]# cat rbd-pv-pod.yaml apiVersion: v1kind: Podmetadata: name: ceph-rbd-pv-pod1spec: containers: - name: ceph-rbd-pv-busybox image: busybox command: ["sleep", "60000"] volumeMounts: - name: ceph-rbd-vol1 mountPath: /mnt/ceph-rbd-pvc/busybox readOnly: false volumes: - name: ceph-rbd-vol1 persistentVolumeClaim: claimName: ceph-rbd-pv-claim [root@elasticsearch01 rbd]# kubectl create -f rbd-pv-pod.yaml pod/ceph-rbd-pv-pod1 created [root@elasticsearch01 rbd]# kubectl get podsNAME READY STATUS RESTARTS AGE busybox 1/1 Running 432 18d ceph-rbd-pv-pod1 0/1 ContainerCreating 0 19s
报错如下
MountVolume.WaitForAttach failed for volume "ceph-rbd-pv" : rbd: map failed exit status 6, rbd output: rbd: sysfs write failed RBD image feature set mismatch. Try disabling features unsupported by the kernel with "rbd feature disable". In some cases useful info is found in syslog - try "dmesg | tail". rbd: map failed: (6) No such device or address
解决方法
禁用一些特性，这些特性在centos7.4内核上不支持，所以生产环境中k8s及相关ceph最好使用内核版本高的系统做为底层操作系统
rbd feature disable rbd-k8s/cephimage2 exclusive-lock object-map fast-diff deep-flatten
[root@ceph01 ~]# rbd feature disable rbd-k8s/cephimage2 exclusive-lock object-map fast-diff deep-flatten
三、验证效果
1、k8s集群端验证
[root@elasticsearch01 rbd]# kubectl get pods -o wideNAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES busybox 1/1 Running 432 18d 10.254.35.3 10.2.8.65 <none> <none> ceph-rbd-pv-pod1 1/1 Running 0 3m39s 10.254.35.8 10.2.8.65 <none> <none> [root@elasticsearch02 ceph]# df -h |grep rbd/dev/rbd0 493G 162G 306G 35% /data /dev/rbd1 20G 45M 20G 1% /var/lib/kubelet/plugins/kubernetes.io/rbd/mounts/rbd-k8s-image-cephimage2 [root@elasticsearch02 ceph]# cd /var/lib/kubelet/plugins/kubernetes.io/rbd/mounts/rbd-k8s-image-cephimage2[root@elasticsearch02 rbd-k8s-image-cephimage2]# lslost+found [root@elasticsearch01 rbd]# kubectl exec -ti ceph-rbd-pv-pod1 sh/ # df -hFilesystem Size Used Available Use% Mounted on overlay 49.1G 7.4G 39.1G 16% / tmpfs 64.0M 0 64.0M 0% /dev tmpfs 7.8G 0 7.8G 0% /sys/fs/cgroup /dev/vda1 49.1G 7.4G 39.1G 16% /dev/termination-log/dev/vda1 49.1G 7.4G 39.1G 16% /etc/resolv.conf /dev/vda1 49.1G 7.4G 39.1G 16% /etc/hostname /dev/vda1 49.1G 7.4G 39.1G 16% /etc/hosts shm 64.0M 0 64.0M 0% /dev/shm /dev/rbd1 19.6G 44.0M 19.5G 0% /mnt/ceph-rbd-pvc/busybox tmpfs 7.8G 12.0K 7.8G 0% /var/run/secrets/kubernetes.io/serviceaccount tmpfs 7.8G 0 7.8G 0% /proc/acpi tmpfs 64.0M 0 64.0M 0% /proc/kcore tmpfs 64.0M 0 64.0M 0% /proc/keys tmpfs 64.0M 0 64.0M 0% /proc/timer_list tmpfs 64.0M 0 64.0M 0% /proc/timer_stats tmpfs 64.0M 0 64.0M 0% /proc/sched_debug tmpfs 7.8G 0 7.8G 0% /proc/scsi tmpfs 7.8G 0 7.8G 0% /sys/firmware / # cd /mnt/ceph-rbd-pvc/busybox//mnt/ceph-rbd-pvc/busybox # lslost+found /mnt/ceph-rbd-pvc/busybox # touch ceph-rbd-pods/mnt/ceph-rbd-pvc/busybox # lsceph-rbd-pods lost+found /mnt/ceph-rbd-pvc/busybox # echo busbox>ceph-rbd-pods /mnt/ceph-rbd-pvc/busybox # cat ceph-rbd-pods busbox [root@elasticsearch02 ceph]# cd /var/lib/kubelet/plugins/kubernetes.io/rbd/mounts/rbd-k8s-image-cephimage2[root@elasticsearch02 rbd-k8s-image-cephimage2]# lsceph-rbd-pods lost+found
2、ceph集群端验证
[root@ceph01 ~]# ceph dfGLOBAL: SIZE AVAIL RAW USED %RAW USED 65.9TiB 58.3TiB 7.53TiB 11.43 POOLS: NAME ID USED %USED MAX AVAIL OBJECTS rbd-es 1 1.38TiB 7.08 18.1TiB 362911 .rgw.root 2 1.14KiB 0 18.1TiB 4 default.rgw.control 3 0B 0 18.1TiB 8 default.rgw.meta 4 46.9KiB 0 104GiB 157 default.rgw.log 5 0B 0 18.1TiB 345 default.rgw.buckets.index 6 0B 0 104GiB 2012 default.rgw.buckets.data 7 1.01TiB 5.30 18.1TiB 2090721 default.rgw.buckets.non-ec 8 0B 0 18.1TiB 0 rbd-k8s 9 137MiB 0 18.1TiB 67
作者：三杯水Plus
链接：https://www.jianshu.com/p/2b6ab2fca08b
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