在nfs服务端执行rpcbind和nfs重启，要按顺序

[root@VM-0-7-centos nfstestdir]# systemctl stop rpcbind
Warning: Stopping rpcbind.service, but it can still be activated by:
  rpcbind.socket
[root@VM-0-7-centos nfstestdir]# systemctl stop nfs
[root@VM-0-7-centos nfstestdir]# systemctl start rpcbind
[root@VM-0-7-centos nfstestdir]# systemctl start nfs

查看mount状态

showmount -e 139.xxx.xxx.xxx

mount:

mkdir /myNfs
mount -t nfs 139.xxx.xxx.xxx:/export/nfs /myNfs