我在服务器上安装了 Ubuntu Server 12.04.2 LTS。运行后
apt-get update & apt-get upgrade & apt-get dist-upgrade
我的内核版本已更改为linux-image-3.5.0-28-generic。 （原来的是linux-image-3.5.0-23-generic）
但是，经过上述操作后，当我运行apt-get upgrade或apt-get autoremove或apt-get install ntp（或其他包）时，shell打印出以下错误信息：
root@network:/boot# apt-get upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
3 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue [Y/n]? y
Setting up linux-image-3.5.0-28-generic (3.5.0-28.48~precise1) ...
Running depmod.
update-initramfs: deferring update (hook will be called later)
Examining /etc/kernel/postinst.d.
run-parts: executing /etc/kernel/postinst.d/apt-auto-removal 3.5.0-28-generic /boot/vmlinuz-3.5.0-28-generic
run-parts: executing /etc/kernel/postinst.d/dkms 3.5.0-28-generic /boot/vmlinuz-3.5.0-28-generic
run-parts: executing /etc/kernel/postinst.d/initramfs-tools 3.5.0-28-generic /boot/vmlinuz-3.5.0-28-generic
update-initramfs: Generating /boot/initrd.img-3.5.0-28-generic
run-parts: executing /etc/kernel/postinst.d/update-notifier 3.5.0-28-generic /boot/vmlinuz-3.5.0-28-generic
run-parts: executing /etc/kernel/postinst.d/zz-update-grub 3.5.0-28-generic /boot/vmlinuz-3.5.0-28-generic
/usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?).
run-parts: /etc/kernel/postinst.d/zz-update-grub exited with return code 1
Failed to process /etc/kernel/postinst.d at /var/lib/dpkg/info/linux-image-3.5.0-28-generic.postinst line 1010.
dpkg: error processing linux-image-3.5.0-28-generic (--configure):
subprocess installed post-installation script returned error exit status 2
E: Sub-process /usr/bin/dpkg returned an error code (1)
有人有什么办法让它工作吗？（我甚至不知道这有什么问题？）或者如何回滚到以前的 Linux 内核版本？（因为以前的版本没有问题linux-image-3.5.0-23-generic。）谢谢！
答案1
通过谷歌，我刚刚发现了问题所在。
实际上，我的问题和
http://ubuntuforums.org/showthread.php?t=1553405
因为我的服务器也是无盘 NFS 启动服务器...
我的问题的解决方案很简单： http://jeffwelling.github.io/2011/08/29/Diskless-Upgrade-Problem.html
exec update-grub只需在文件中注释掉即可/etc/kernel/postinst.d/zz-update-grub。
（NFS 启动不需要 grub。）
谢谢！