这是我的 Ubuntu 20.10，如果我理解正确的话，uname 会显示错误版本
# uname -r
4.15.0-60-generic
因为
# ls -la /boot
total 147492
drwxr-xr-x 4 root root 4096 Feb 11 21:21 .
drwxr-xr-x 19 root root 4096 Feb 11 01:07 ..
-rw-r--r-- 1 root root 248258 Jan 18 17:01 config-5.8.0-41-generic
-rw-r--r-- 1 root root 248258 Feb 5 03:41 config-5.8.0-43-generic
drwxr-xr-x 4 root root 4096 Feb 11 21:21 grub
lrwxrwxrwx 1 root root 27 Feb 11 21:21 initrd.img -> initrd.img-5.8.0-43-generic
-rw-r--r-- 1 root root 55795996 Feb 11 01:07 initrd.img-5.8.0-41-generic
-rw-r--r-- 1 root root 55798352 Feb 11 21:21 initrd.img-5.8.0-43-generic
lrwxrwxrwx 1 root root 27 Jan 28 07:27 initrd.img.old -> initrd.img-5.8.0-41-generic
drwx------ 2 root root 16384 Feb 11 01:07 lost+found
-rw------- 1 root root 5635676 Jan 18 17:01 System.map-5.8.0-41-generic
-rw------- 1 root root 5635676 Feb 5 03:41 System.map-5.8.0-43-generic
lrwxrwxrwx 1 root root 24 Feb 11 21:21 vmlinuz -> vmlinuz-5.8.0-43-generic
-rw------- 1 root root 13715296 Jan 18 17:08 vmlinuz-5.8.0-41-generic
-rw------- 1 root root 13715296 Feb 5 04:04 vmlinuz-5.8.0-43-generic
lrwxrwxrwx 1 root root 24 Jan 28 07:27 vmlinuz.old -> vmlinuz-5.8.0-41-generic
# dpkg -l | grep linux-
ii linux-base 4.5ubuntu4 all Linux image base package
ii linux-firmware 1.190.3 all Firmware for Linux kernel drivers
ii linux-generic 5.8.0.43.48 amd64 Complete Generic Linux kernel and headers
ii linux-headers-5.8.0-41 5.8.0-41.46 all Header files related to Linux kernel version 5.8.0
ii linux-headers-5.8.0-41-generic 5.8.0-41.46 amd64 Linux kernel headers for version 5.8.0 on 64 bit x86 SMP
ii linux-headers-5.8.0-43 5.8.0-43.49 all Header files related to Linux kernel version 5.8.0
ii linux-headers-5.8.0-43-generic 5.8.0-43.49 amd64 Linux kernel headers for version 5.8.0 on 64 bit x86 SMP
ii linux-headers-generic 5.8.0.43.48 amd64 Generic Linux kernel headers
ii linux-image-5.8.0-41-generic 5.8.0-41.46 amd64 Signed kernel image generic
ii linux-image-5.8.0-43-generic 5.8.0-43.49 amd64 Signed kernel image generic
ii linux-image-generic 5.8.0.43.48 amd64 Generic Linux kernel image
ii linux-modules-5.8.0-41-generic 5.8.0-41.46 amd64 Linux kernel extra modules for version 5.8.0 on 64 bit x86 SMP
ii linux-modules-5.8.0-43-generic 5.8.0-43.49 amd64 Linux kernel extra modules for version 5.8.0 on 64 bit x86 SMP
ii linux-modules-extra-5.8.0-41-generic 5.8.0-41.46 amd64 Linux kernel extra modules for version 5.8.0 on 64 bit x86 SMP
ii linux-modules-extra-5.8.0-43-generic 5.8.0-43.49 amd64 Linux kernel extra modules for version 5.8.0 on 64 bit x86 SMP
# ls -lha /lib/modules
total 16K
drwxr-xr-x 4 root root 4.0K Feb 11 21:21 .
drwxr-xr-x 47 root root 4.0K Feb 11 21:22 ..
drwxr-xr-x 5 root root 4.0K Jan 28 07:27 5.8.0-41-generic
drwxr-xr-x 5 root root 4.0K Feb 11 21:21 5.8.0-43-generic
当我尝试安装 UFW 时，收到错误 错误：无法确定 iptables 版本 我见过 iptables 版本
# update-alternatives --list iptables
/usr/sbin/iptables-legacy
/usr/sbin/iptables-nft
并切换到旧版本
# update-alternatives --set iptables /usr/sbin/iptables-legacy
并重新启动。但 UFW 仍然不起作用。
# sudo iptables --list
modprobe: FATAL: Module ip_tables not found in directory /lib/modules/4.15.0-60-generic
iptables v1.8.5 (legacy): can't initialize iptables table `filter': Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.
# depmod
depmod: ERROR: could not open directory /lib/modules/4.15.0-60-generic: No such file or directory
depmod: FATAL: could not search modules: No such file or directory
# ufw status verbose
ERROR: problem running iptables: modprobe: FATAL: Module ip_tables not found in directory /lib/modules/4.15.0-60-generic
iptables v1.8.5 (legacy): can't initialize iptables table `filter': Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.
如何修复这个 ubuntu（参见 Uname）并以正确的方式安装 UFW？
答案1
我终于理解了这个问题。这就是我们对云提供商的全部了解，他们的脚本将操作系统安装到一个磁盘（在我的情况下是 /dev/sdb Ubuntu 20.10），而不是从另一个磁盘启动系统（在我的情况下是 /dev/sda 和 Ubuntu 16.04）