1 - 更新Linux内核
更新Linux内核
简单更新小版本
在ssh登录到ubuntu server时，有时会看到类似的提示：
10 updates can be applied immediately.
To see these additional updates run: apt list --upgradable
查看具体内容:
sudo apt list --upgradable
[sudo] password for sky:
Listing... Done
linux-generic/focal-proposed 5.4.0.97.101 amd64 [upgradable from: 5.4.0.96.100]
linux-headers-generic/focal-proposed 5.4.0.97.101 amd64 [upgradable from: 5.4.0.96.100]
linux-image-generic/focal-proposed 5.4.0.97.101 amd64 [upgradable from: 5.4.0.96.100]
linux-libc-dev/focal-proposed 5.4.0-97.110 amd64 [upgradable from: 5.4.0-96.109]
通常这种都是小版本的更新提示，比如我这里就是安装了 5.4.0-96 然后提示有 5.4.0-97 版本的更新。
升级也非常简单：
sudo apt upgrade
过程中相对复杂的已有的 dkms 模块要在新内核上重新编译，一般时间会比较长。
升级晚之后重启，然后检查一下 dkms：
dkms status
iser, 4.9, 5.4.0-94-generic, x86_64: installed
iser, 4.9, 5.4.0-96-generic, x86_64: installed
iser, 4.9, 5.4.0-97-generic, x86_64: installed
isert, 4.9, 5.4.0-94-generic, x86_64: installed
isert, 4.9, 5.4.0-96-generic, x86_64: installed
isert, 4.9, 5.4.0-97-generic, x86_64: installed
kernel-mft-dkms, 4.15.1, 5.4.0-94-generic, x86_64: installed
kernel-mft-dkms, 4.15.1, 5.4.0-96-generic, x86_64: installed
kernel-mft-dkms, 4.15.1, 5.4.0-97-generic, x86_64: installed
knem, 1.1.4.90mlnx1, 5.4.0-94-generic, x86_64: installed
knem, 1.1.4.90mlnx1, 5.4.0-96-generic, x86_64: installed
knem, 1.1.4.90mlnx1, 5.4.0-97-generic, x86_64: installed
mlnx-ofed-kernel, 4.9, 5.4.0-94-generic, x86_64: installed
mlnx-ofed-kernel, 4.9, 5.4.0-96-generic, x86_64: installed
mlnx-ofed-kernel, 4.9, 5.4.0-97-generic, x86_64: installed
rshim, 1.18, 5.4.0-94-generic, x86_64: installed
rshim, 1.18, 5.4.0-96-generic, x86_64: installed
rshim, 1.18, 5.4.0-97-generic, x86_64: installed
srp, 4.9, 5.4.0-94-generic, x86_64: installed
srp, 4.9, 5.4.0-96-generic, x86_64: installed
srp, 4.9, 5.4.0-97-generic, x86_64: installed
我这里因为有多个内核版本，所以模块比较多，后面会删除不用的旧版本内核。
手动更新大版本
对于大版本更新，需要手工。
考虑到 22.04 版本不稳定，试用之下发现有一些莫名其妙的问题，不想折腾，继续试用 20.04版本，但是希望可以把内核从 5.4 升级到更新的版本，比如 5.15.
先看一下有哪些版本可以选择：
sudo apt update
# 下面这个 apt list 命令要在 bash 下才能成功，先临时切换到 bash
bash
sudo apt list linux-headers-5.15.*-*-generic linux-image-5.15.*-*-generic
linux-headers-5.15.0-33-generic/focal-updates,focal-security 5.15.0-33.34~20.04.1 amd64
linux-headers-5.15.0-41-generic/focal-updates,focal-security 5.15.0-41.44~20.04.1 amd64
linux-headers-5.15.0-43-generic/focal-updates,focal-security 5.15.0-43.46~20.04.1 amd64
linux-headers-5.15.0-46-generic/focal-updates,focal-security 5.15.0-46.49~20.04.1 amd64
linux-headers-5.15.0-48-generic/focal-updates,focal-security 5.15.0-48.54~20.04.1 amd64
linux-headers-5.15.0-50-generic/focal-updates,focal-security 5.15.0-50.56~20.04.1 amd64
linux-headers-5.15.0-52-generic/focal-updates,focal-security 5.15.0-52.58~20.04.1 amd64
linux-headers-5.15.0-53-generic/focal-updates,focal-security 5.15.0-53.59~20.04.1 amd64
linux-headers-5.15.0-56-generic/focal-updates,focal-security 5.15.0-56.62~20.04.1 amd64
linux-headers-5.15.0-57-generic/focal-updates,focal-security 5.15.0-57.63~20.04.1 amd64
linux-headers-5.15.0-58-generic/focal-updates,focal-security 5.15.0-58.64~20.04.1 amd64
linux-image-5.15.0-33-generic/focal-updates,focal-security 5.15.0-33.34~20.04.1 amd64
linux-image-5.15.0-41-generic/focal-updates,focal-security 5.15.0-41.44~20.04.1 amd64
linux-image-5.15.0-43-generic/focal-updates,focal-security 5.15.0-43.46~20.04.1 amd64
linux-image-5.15.0-46-generic/focal-updates,focal-security 5.15.0-46.49~20.04.1 amd64
linux-image-5.15.0-48-generic/focal-updates,focal-security 5.15.0-48.54~20.04.1 amd64
linux-image-5.15.0-50-generic/focal-updates,focal-security 5.15.0-50.56~20.04.1 amd64
linux-image-5.15.0-52-generic/focal-updates,focal-security 5.15.0-52.58~20.04.1 amd64
linux-image-5.15.0-53-generic/focal-updates,focal-security 5.15.0-53.59~20.04.1 amd64
linux-image-5.15.0-56-generic/focal-updates,focal-security 5.15.0-56.62~20.04.1 amd64
linux-image-5.15.0-57-generic/focal-updates,focal-security 5.15.0-57.63~20.04.1 amd64
linux-image-5.15.0-58-generic/focal-updates,focal-security 5.15.0-58.64~20.04.1 amd64
试试最新的 5.15.0-58
sudo apt install linux-headers-5.15.0-58-generic linux-image-5.15.0-58-generic
安装完成后重启，检查：
uname -a
Linux skyserver 5.15.0-58-generic #64~20.04.1-Ubuntu SMP Fri Jan 6 16:42:31 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
可以看到 linux 内核已经更新到 5.15。
但这只是升级内核，发行版本还是会继续保持不变：
lsb_release -a
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04.5 LTS
Release: 20.04
Codename: focal
参考资料：
2 - 删除Linux内核
删除不用的Linux内核
多次升级之后，系统内就会累计有多个内核版本，可以考虑删除旧的不用的内核。
参考：
https://askubuntu.com/questions/1253347/how-to-easily-remove-old-kernels-in-ubuntu-20-04-lts
vi remove_old_kernels.sh
新建一个文件内容如下：
#!/bin/bash
# Run this script without any param for a dry run
# Run the script with root and with exec param for removing old kernels after checking
# the list printed in the dry run
uname -a
IN_USE=$(uname -a | awk '{ print $3 }')
if [[ $IN_USE == *-generic ]]
then
IN_USE=${IN_USE::-8}
fi
echo "Your in use kernel is $IN_USE"
OLD_KERNELS=$(
dpkg --list |
grep -v "$IN_USE" |
grep -v "linux-headers-generic" |
grep -v "linux-image-generic" |
grep -Ei 'linux-image|linux-headers|linux-modules' |
awk '{ print $2 }'
)
echo "Old Kernels to be removed:"
echo "$OLD_KERNELS"
if [ "$1" == "exec" ]; then
for PACKAGE in $OLD_KERNELS; do
yes | apt purge "$PACKAGE"
done
fi
执行
bash ./remove_old_kernels.sh
看查看到要删除的内核版本和相关的包，确认没有问题之后再通过
sudo bash ./remove_old_kernels.sh exec
进行实际删除。
之后重启，执行：
dpkg --list | grep -Ei 'linux-image|linux-headers|linux-modules'
检查现有的内核：
ii linux-headers-5.4.0-97 5.4.0-97.110 all Header files related to Linux kernel version 5.4.0
ii linux-headers-5.4.0-97-generic 5.4.0-97.110 amd64 Linux kernel headers for version 5.4.0 on 64 bit x86 SMP
ii linux-headers-generic 5.4.0.97.101 amd64 Generic Linux kernel headers
ii linux-image-5.4.0-97-generic 5.4.0-97.110 amd64 Signed kernel image generic
ii linux-image-generic 5.4.0.97.101 amd64 Generic Linux kernel image
ii linux-modules-5.4.0-97-generic 5.4.0-97.110 amd64 Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
ii linux-modules-extra-5.4.0-97-generic 5.4.0-97.110 amd64 Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP