一.背景
不知道挂载点这个表述是否准确。真实的需求是有个时候删除rbd块会提示当前rbd正在使用中，如法删除。对于linux下是文件或者目录可以通过lsof查看当前文件或目录的使用进程。对于ceph也希望有一个合适的方式查看当前rbd块在哪个主机上被使用。
二.解决方法
对于rbd块的使用，目前主要有两种形式：内核模块map后再mount和通过libvirt等供给虚拟机使用。两种方式不太一样。
2.1 内核模块map
查看方法如下：
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| ##查看rbd池下的rbd
root@node-62:~# rbd ls
gci
##查看gci的挂载点
root@node-62:~# rados -p rbd listwatchers gci.rbd
watcher=10.1.41.205:0/1642395845 client.5493237 cookie=2
##去挂载点检查
root@node-67:~# rbd showmapped |grep gci
2 rbd gci - /dev/rbd2
|
2.1 虚拟机通过libvirt使用rbd
查看方法如下：
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| ##查看该虚拟机卷的信息
root@node-67:~# rbd info volume-997d91e8-40f3-4ede-affb-8b61775fccde -p volumes
rbd image 'volume-997d91e8-40f3-4ede-affb-8b61775fccde':
size 300 GB in 76800 objects
order 22 (4096 kB objects)
block_name_prefix: rbd_data.10475c6f9a52
format: 2
features: layering
parent: volumes/volume-4461e760-8c3d-4e7f-9537-c27b301a74c2@snapshot-d17bc874-c589-4118-b6af-058f1c6e3a02
overlap: 300 GB
##查看该卷的挂载点
root@node-67:~# rados -p volumes listwatchers rbd_header.10475c6f9a52
watcher=10.1.41.201:0/1001261 client.4449991 cookie=1
## 通过nova show验证该卷是否在物理机10.1.41.201(node-63)上
root@node-67:~# nova show zhoulin_UbuntuKylin_0824
+--------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------+
| Property | Value |
+--------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------+
| OS-DCF:diskConfig | AUTO |
| OS-EXT-AZ:availability_zone | nova |
| OS-EXT-SRV-ATTR:host | node-63 |
| OS-EXT-SRV-ATTR:hypervisor_hostname | node-63 |
| OS-EXT-SRV-ATTR:instance_name | instance-00000086 |
| OS-EXT-STS:power_state | 1 |
| OS-EXT-STS:task_state | - |
| OS-EXT-STS:vm_state | active |
| OS-SRV-USG:launched_at | 2015-08-24T02:14:34.000000 |
| OS-SRV-USG:terminated_at | - |
| accessIPv4 | |
| accessIPv6 | |
| config_drive | |
| created | 2015-08-24T02:14:28Z |
| flavor | m1.large (903620b6-e4e2-49a7-bcca-38139b9d4e30) |
| hostId | 73f6a8472a61da98b5ecbf7a5b7a94791991bdc69a94f3fe984f58dc |
| id | 3b5a16f5-b2a3-4e74-95c0-bd3e2114016a |
| image | Attempt to boot from volume - no image supplied |
| key_name | ubuntu |
| metadata | {} |
| name | zhoulin_UbuntuKylin_0824 |
| novanetwork network | |
| os-extended-volumes:volumes_attached | [{"id": "997d91e8-40f3-4ede-affb-8b61775fccde"}, {"id": "5f9ba54a-c7e1-441a-b28c-180995accec1"}, {"id": "8256288a-fca8-4d70-9d8e-f1a0a7821a1a"}] |
| progress | 0 |
| security_groups | default |
| status | ACTIVE |
| tenant_id | 26d260968b1e4a8caa9356aafff090e6 |
| updated | 2016-01-31T01:51:12Z |
| user_id | c18a490fffb846fc9d52aa62b4d07ae2 |
+--------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------+
|
三.总结
基本都是利用rados listwatchers去查看，只是两种方式需要读取的文件不一样。
