在操作 openstack NFS volume 時，遇到較多的問題都在於 permission case 1: 當要 attach volume 到 instance 時，遇到 ERROR Device is busy 從 compute node 上的 nova log 看到這些錯誤訊息 2017-01-03 14:25:44.550 46261 ERROR nova.virt.block_device [instance: 35bedaff-07a9-41d7-bdfa-930fc569cdef] File "/openstack/venvs/nova-13.3.10/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 1355, in attach_volume 2017-01-03 14:25:44.550 46261 ERROR nova.virt.block_device [instance: 35bedaff-07a9-41d7-bdfa-930fc569cdef] raise exception.DeviceIsBusy(device=disk_dev) 2017-01-03 14:25:44.550 46261 ERROR nova.virt.block_device [instance: 35bedaff-07a9-41d7-bdfa-930fc569cdef] DeviceIsBusy: The supplied device (vdb) is busy. 解決方式: 先把 instance shutdown 就可以 attach 了 case 2: 當 attach volume 完成後，要 start instance 發生的 ERROR qemu-system-x86_64: -drive file=/var/lib/nova/mnt/6d38f8c2da18e2e39ce88cca0f73414a/volume-947f95f1-d90b-41a2-b9ce-c3b03ad1dcdd,if=none,id=drive-virtio-disk1,format=raw,serial=947f95f1-d90...