注意红色部分。今天遇到相似问题。
sudo vi /etc/default/nfs-kernel-server
# Number of servers to start up
2 #RPCNFSDCOUNT=8
3 RPCNFSDCOUNT="-V 2 8"
4 # Runtime priority of server (see nice(1))
5 RPCNFSDPRIORITY=0
6
7 # Options for rpc.mountd.
8 # If you have a port-based firewall, you might want to set up
9 # a fixed port here using the --port option. For more information,
10 # see rpc.mountd(8) or http://wiki.debian.org/SecuringNFS
11 # To disable NFSv4 on the server, specify '--no-nfs-version 4' here
12 RPCMOUNTDOPTS="-V 2 --manage-gids"
13
14 # Do you want to start the svcgssd daemon? It is only required for Kerberos
15 # exports. Valid alternatives are "yes" and "no"; the default is "no".
16 NEED_SVCGSSD=""
17
18 # Options for rpc.svcgssd.
19 RPCSVCGSSDOPTS="--nfs-version 2,3,4 --debug --syslog"