升级后，NFS 模块停止加载到内核，/proc/fs/nfsd停止被挂载。
使用 modprobe 加载 NFS 模块成功安装，但尝试时mount -t nfsd /proc/fs/nfsd，它会抱怨不在 中/etc/fstab。由于nfsd未安装，所有其他 NFS 服务都会失败。
报道内容如下systemd：
May 10 04:46:49 Cuckoo-Database systemd[1]: nfs-idmapd.service: Job nfs-idmapd.service/start failed with result 'dependency'.
May 10 04:46:49 Cuckoo-Database systemd[1]: Dependency failed for NFS Mount Daemon.
-- Subject: A start job for unit nfs-mountd.service has failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- A start job for unit nfs-mountd.service has finished with a failure.
--
-- The job identifier is 984 and the job result is dependency.
May 10 04:46:49 Cuckoo-Database systemd[1]: nfs-mountd.service: Job nfs-mountd.service/start failed with result 'dependency'.
May 10 04:46:49 Cuckoo-Database systemd[1]: nfs-server.service: Job nfs-server.service/start failed with result 'dependency'.
May 10 04:46:49 Cuckoo-Database systemd[1]: nfs-idmapd.service: Unit is bound to inactive unit nfs-server.service. Stopping, too.
May 10 04:46:49 Cuckoo-Database systemd[1]: Stopping NFSv4 ID-name mapping service...
我尝试重新安装nfs-common和nfs-kernel-server，但这并不能解决问题。