1. what is nfs used for?

nfs is network file system, it is used when multiple computers need to access one directory.

2. Computer Environment

OS: Ubuntu 20.04

3. Install and config nfs server

3.1. Install nfs server

#执行以下命令安装NFS服务器，
​#apt会自动安装nfs-common、rpcbind等13个软件包
​sudo apt install nfs-kernel-server

3.2 create directory to share

# create directory /home/maye/nfs  to share on nfs server host
# Attention: It's better to create directory to share under directory home, not under root directory, 
# because It may have error: permission not allowed to read or write the directory, 
# if under root directory.
sudo mkdir -p /home/maye/nfs
​

3.3 write config file to set exported directories.

sudo gedit /etc/exports

-->
#设置共享目录
/home/maye/nfs *(rw,sync,no_subtree_check,no_root_squash)```

Note:
* means any ip can mount this exported directory.

3.4 start nfs service

# before starting nds serivce, rpcbind service needs to be active.
# check status of rpcbind service
$ systemctl status rpcbind
# if rpcbind service not active, start it.
$ systemctl start rpcbind  
$ systemctl start nfs-kernel-server

# see the export list for localhost
$ showmount -e

-->
Export list for maye-Inspiron-5547:
/home/maye/nfs *

4. Install and config nfs client

4.1 install nfs client

#在需要连接到NFS服务器的客户端机器上，
#需要执行以下命令，安装nfs-common软件包。
#apt会自动安装nfs-common、rpcbind等12个软件包
sudo apt install nfs-common

#显示指定的NFS服务器上export出来的目录
sudo showmount -e nfs-server-ip

4.2 create directory which the nfs server exported directory will mount to.

sudo mkdir -p /home/maye/mnt/nfs

4.3 mount shared directory

# on nfs client
# /home/maye/nfs is the directory exported on nfs server in this example, 
# /home/maye/mnt/nfs is the directory on nfs server to which 
# to mount the shared directory in this example,
# change them to the actual pathes in your case.
sudo mount -t nfs nfs-server-ip:/home/maye/nfs /home/maye/mnt/nfs 

# check the mounted directory
$ sudo df -h

-->
nfs-server-ip:/home/maye/nfs 457G 182G 253G 42% /home/maye/mnt/nfs

5. stop nfs service

# on nfs server
$ sudo systemctl stop nfs-kernel-server

References:
https://zhuanlan.zhihu.com/p/606174368?utm_id=0