CephFS namespaces can be exported over NFS protocol using the NFS-Ganesha NFS
server. This document provides information on configuring NFS-Ganesha
clusters manually. The simplest and preferred way of managing NFS-Ganesha
clusters and CephFS exports is using
ceph nfs ... commands. See
CephFS & RGW Exports over NFS for more details. As the deployment is done using cephadm or
Ceph file system (preferably latest stable luminous or higher versions)
In the NFS server host machine, ‘libcephfs2’ (preferably latest stable luminous or higher), ‘nfs-ganesha’ and ‘nfs-ganesha-ceph’ packages (latest ganesha v2.5 stable or higher versions)
NFS-Ganesha server host connected to the Ceph public network
It is recommended to use 3.5 or later stable version of NFS-Ganesha packages with pacific (16.2.x) or later stable version of Ceph packages.
Configuring NFS-Ganesha to export CephFS¶
NFS-Ganesha provides a File System Abstraction Layer (FSAL) to plug in different storage backends. FSAL_CEPH is the plugin FSAL for CephFS. For each NFS-Ganesha export, FSAL_CEPH uses a libcephfs client, user-space CephFS client, to mount the CephFS path that NFS-Ganesha exports.
Setting up NFS-Ganesha with CephFS, involves setting up NFS-Ganesha’s configuration file, and also setting up a Ceph configuration file and cephx access credentials for the Ceph clients created by NFS-Ganesha to access CephFS.
A sample ganesha.conf configured with FSAL_CEPH can be found here, https://github.com/nfs-ganesha/nfs-ganesha/blob/next/src/config_samples/ceph.conf. It is suitable for a standalone NFS-Ganesha server, or an active/passive configuration of NFS-Ganesha servers managed by some sort of clustering software (e.g., Pacemaker). Important details about the options are added as comments in the sample conf. There are options to do the following:
minimize Ganesha caching wherever possible since the libcephfs clients (of FSAL_CEPH) also cache aggressively
read from Ganesha config files stored in RADOS objects
store client recovery data in RADOS OMAP key-value interface
mandate NFSv4.1+ access
enable read delegations (need at least v13.0.1 ‘libcephfs2’ package and v2.6.0 stable ‘nfs-ganesha’ and ‘nfs-ganesha-ceph’ packages)
Configuration for libcephfs clients¶
Required ceph.conf for libcephfs clients includes:
a [client] section with
mon_hostoption set to let the clients connect to the Ceph cluster’s monitors, usually generated via
ceph config generate-minimal-conf, e.g.,
[global] mon host = [v2:192.168.1.7:3300,v1:192.168.1.7:6789], [v2:192.168.1.8:3300,v1:192.168.1.8:6789], [v2:192.168.1.9:3300,v1:192.168.1.9:6789]
Mount using NFSv4 clients¶
It is preferred to mount the NFS-Ganesha exports using NFSv4.1+ protocols to get the benefit of sessions.
Conventions for mounting NFS resources are platform-specific. The following conventions work on Linux and some Unix platforms:
mount -t nfs -o nfsvers=4.1,proto=tcp <ganesha-host-name>:<ganesha-pseudo-path> <mount-point>