What Is Linux nfsd Process and Meaning?
NFS is Unix and Linux type network based file system. This file system is served over network. In order to serve file system with files and directory nfsd daemon is used. It is actually a kernel module with a service. NFS is the short form of Network Files System.
Installation
We can install NFS client tools and service with the following commands.
Ubuntu, Debian, Mint, Kali:
Following command will install client tools.
1 | $ sudo apt install nfs-common |
and with the following nfs-kernel-server package we will install server daemon.
1 | $ sudo apt install nfs-kernel-server |
Install NFS Client and Server
CentOS, Fedora, RHEL:
1 | $ sudo yum install nfs-utils nfs-utils-lib |
Versions NFSv2, NFSv3,NFSv4
NFS has different versions to use. Most recent version is v4. There are some major differences about versions. Most of the systems runs NFSv3 and NFSv4
Configuration File
NFS service has a default configuration which is stored as /usr/share/nfs-kernel-server/conffiles/nfs-kernel-server.default . We can view an change it like below.
1 | $ sudo vim /usr/share/nfs-kernel-server/conffiles/nfs-kernel-server.default |
NFS Configuration File
There is following configuration options to change.
RPCNFSDCOUNTwill set number of NFSD servers which will start.RPCNFSDPRIORITYwill set the process priority of the NFSD. Higher numbers will make our NFSD server more performative.RPCMOUNTDOPTSis used to setrpcmount options.NEED_SVCGSSDis used for Kerberos authentication for exports. The default value isnowhich will disable Kerberos authentication.- During start of the NFSD we may want to provide some options the the
rpc.svcgssd. We can set it withRPCSVCGSSDOPTS.
Share Files and Directories
Files sharing is the main purpose of the NFS service or NFSD . The file share is stored in the /etc/export file like below.
1 | $ cat /etc/exports |
Share Files and Directories
As we can see there are some example configurations which are not active. In this example we will share /mtn directory to the all of the remote systems.
1 | /mnt * |
In this example we will share /mnt to the only to the systems reside in 192.168.1.0/24
1 | /mnt 192.168.1.0/24 |
We can also share the given path with a single remote system which is 192.168.1.10 in this example.
1 | /mnt 192.168.1.10 |
Difference Between NFS and NFSD
NFSD is a user level process but do not have any function to process NFS requests. NFSD redirects requests tot eh kernel transport endpoint and invokes a in-kernel process to process request and respond to the client. NFSD is the server side.
NFS is the client side and each process accessing an NFS file system will make its own RPC request to the remote NFSD or NFS server.
