挂载虚拟机的时候报错如下：

~ # mount  10.10.8.166:/home/ytj/hi3516/nfs /userdata/xinying/
mount: mounting 10.10.8.166:/home/ytj/hi3516/nfs on /userdata/xinying/ failed: No route to host
~ # mount -t nfs -nolock 10.10.8.166:/home/ytj/hi3516/nfs /userdata/xinying/
mount: mounting 10.10.8.166:/home/ytj/hi3516/nfs on /userdata/xinying/ failed: No route to host
~ # ping 10.10.8.166
PING 10.10.8.166 (10.10.8.166): 56 data bytes
64 bytes from 10.10.8.166: seq=0 ttl=64 time=0.637 ms
64 bytes from 10.10.8.166: seq=1 ttl=64 time=0.735 ms

查了一下，都说看看防火墙的状态，关闭防火墙（虚拟机和服务器的IP都可以ping通）
查看防火墙状态 ufw status

root@ubuntu:/home/ytj# ufw status
Status: inactive

还是不行
试了半天，用另一个命令查看防火墙状态

systemctl status firewalld.service
systemctl status firewalld 

root@ubuntu:/home/ytj# systemctl status firewalld.service
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
   Active: active (running) since Tue 2021-07-27 20:24:57 PDT; 2h 40min ago
 Main PID: 881 (firewalld)
   CGroup: /system.slice/firewalld.service
           └─881 /usr/bin/python3 -Es /usr/sbin/firewalld --nofork --nopid
root@ubuntu:/home/ytj# systemctl status firewalld 
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
   Active: active (running) since Tue 2021-07-27 20:24:57 PDT; 2h 46min ago
 Main PID: 881 (firewalld)
   CGroup: /system.slice/firewalld.service
           └─881 /usr/bin/python3 -Es /usr/sbin/firewalld --nofork --nopid

这防火墙应该是开着呢，运行

systemctl stop firewalld

关闭防火墙

root@ubuntu:/home/ytj# systemctl stop firewalld
root@ubuntu:/home/ytj# systemctl status firewalld 
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
   Active: inactive (dead) since Tue 2021-07-27 23:12:14 PDT; 2s ago
  Process: 881 ExecStart=/usr/sbin/firewalld --nofork --nopid (code=exited, status=0/SUCCESS)
 Main PID: 881 (code=exited, status=0/SUCCESS)

唉，这咋不同命令结果还不一样的，懂的小伙伴留个言解释一下
然后再挂载就是报超时, 暂未解决

—————————————————更新线————————————————————————
大佬同事过来帮我一顿操作就好了，真奇怪，他的操作平平无奇，我都已经做过了呀，重启nfs服务等等

sudo /etc/init.d/nfs-kernel-server restart

后来我终于发现问题了，命令写的不对，我运行的命令

mount -t nfs -nolock 10.10.71.78:/home/ytj/hi3516/nfs /userdata/xinying/

他运行的命令

mount -t nfs -o nolock 10.10.71.78:/home/ytj/hi3516/nfs /userdata/xinying

仔细看，参数那我把 -o 和nolock写在一起了，唉，你妹的，也不报个错，就一直是超时，我还关了windows上的防火墙，改成桥接模式等等，好气。。。。。

以后一定要仔细，谨记。