K8s integration

[xin3liang]

This topic is derived from another topic: #724
How to integrate the Ceph NVMe-oF Gateway with K8s?
And what should be done? Write a gateway client to do similar things as rbd-nbd?

Per my understanding, we should do something inside Ceph-CSI handling the data path setup and disk attachment.
Does the team have any plan for K8s integration?

Or is it necessary?
The current Ceph-CSI data path is based on Librbd.
Is it necessary to do an RBD image to NVMe-oF conversion for Ceph-CSI? What are the benefits?

[oritwas]

We need the following work to integrate with k8s:

• Run the NVMe-oF gateway in the k8s cluster using Rook as it does not support it currently
• Adding support of it to the Ceph CSI (similar to what was done for NFS)

We can allow connecting to the NVMe-oF in the application directly if we deploy it with host networking.
Most k8s users prefer CSI naturally.