ceph-csi/docs/rbd-nbd.md
Prasanna Kumar Kalever 85a1fba0f4 doc: update rbd-nbd documentation with volume expansion support details
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>
2021-08-10 13:21:16 +00:00

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RBD NBD Mounter

Overview

The RBD CSI plugin will provision new RBD images and attach and mount those to workloads. Currently, the default mounter is krbd, which uses the kernel rbd driver to mount the rbd images onto the application node. Here on at ceph-csi we will also have a userspace way of mounting the RBD images, via RBD-NBD.

Rbd-nbd is a client for RADOS block device (rbd) images like the existing rbd kernel module. It will map an rbd image to an NBD (Network Block Device) device, allowing access to it as a regular local block device.

Its worth to make a note that the rbd-nbd processes will run on the client-side, which is inside the csi-rbdplugin node plugin.

Configuration

To use the rbd-nbd mounter for RBD-backed PVs, set mounter to rbd-nbd in the StorageClass.

Status

Rbd-nbd support status: Alpha

Support Matrix

Features Feature Status CSI Driver Version Ceph Cluster Version CSI Spec Version Kubernetes Version
Creating and deleting snapshot Alpha >= v3.4.0 Pacific (>=16.0.0) >= v1.0.0 >= v1.17.0
Creating and deleting clones Alpha >= v3.4.0 Pacific (>=16.0.0) >= v1.0.0 >= v1.17.0
Expand volumes Alpha >= v3.4.0 Pacific (>=16.0.0) >= v1.1.0 >= v1.15.0

NOTE: The Alpha status reflects possible non-backward compatible changes in the future, and is thus not recommended for production use.

CSI spec and Kubernetes version compatibility

Please refer to the matrix in the Kubernetes documentation.