Ceph RBD-NBD support

[imquanquan]

Is this a BUG REPORT or FEATURE REQUEST?:

Uncomment only one, leave it on its own line:

/kind bug

/kind feature

Add support for the rbd-nbd feature-rich client to improve support for Ceph RBD.

The CSI plugin offers support for Ceph RBD based on the krbd kernel client. Unfortunately, krbd can't use the librbd user-space space library that gets most of the development focus.This caused a feature gap problems.It will cause the volume in OpenSDS fail to mount.

Beside the feature gap krbd exhibits additional drawback. Being entirely kernel space impacts fault-tolerance as any kernel panic affects a whole node -- not only a single Pod using RBD storage.

Those issues can be addressed by employing rbd-nbd -- a thin adapter between NBD subsystem of Linux kernel and librbd.

[leonwanghui]

Hi @xing-yang , have you deep a bit dive into this issue?

[xing-yang]

Hi @leonwanghui This seems to be a useful feature. If someone from the community can help develop it, that will be great.

[skdwriting]

adding to backlog and "help needed"