2020 July 07 Linux

Ubuntu 内核管理

查看内核

# 查看内核列表
sudo dpkg --get-selections | grep linux-image

# Linux 已安装内核：
dpkg --get-selections | grep linux
# or
dpkg --list | grep linux

安装内核

# 显示所有可以获取的内核版本
apt-cache search linux
# 安装指定版本 <version> 内核
sudo apt-get install  -y linux-headers-<version>-generic \
                        linux-image-<version>-generic \
                        linux-image-extra-<version>-generic

删除内核

```bash
# 删除多余内核
sudo apt-get purge linux-image-<版本号> 命令
```

切换内核

查找内核名称

 grep menuentry /boot/grub/grub.cfg

 # if [ x"${feature_menuentry_id}" = xy ]; then
 #   menuentry_id_option="--id"
 #   menuentry_id_option=""
 # export menuentry_id_option
 # menuentry 'Ubuntu' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-078e99ce-eb46-4324-bd9b-6dc10573508b' {
 # submenu 'Advanced options for Ubuntu' $menuentry_id_option 'gnulinux-advanced-078e99ce-eb46-4324-bd9b-6dc10573508b' {
 # 	menuentry 'Ubuntu, with Linux 4.4.0-184-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-184-generic-advanced-078e99ce-eb46-4324-bd9b-6dc10573508b' {
 # 	menuentry 'Ubuntu, with Linux 4.4.0-184-generic (upstart)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-184-generic-init-upstart-078e99ce-eb46-4324-bd9b-6dc10573508b' {
 # 	menuentry 'Ubuntu, with Linux 4.4.0-184-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-184-generic-recovery-078e99ce-eb46-4324-bd9b-6dc10573508b' {
 # 	menuentry 'Ubuntu, with Linux 4.4.0-179-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-179-generic-advanced-078e99ce-eb46-4324-bd9b-6dc10573508b' {
 # 	menuentry 'Ubuntu, with Linux 4.4.0-179-generic (upstart)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-179-generic-init-upstart-078e99ce-eb46-4324-bd9b-6dc10573508b' {
 # 	menuentry 'Ubuntu, with Linux 4.4.0-179-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-179-generic-recovery-078e99ce-eb46-4324-bd9b-6dc10573508b' {
 # 	menuentry 'Ubuntu, with Linux 4.4.0-178-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-178-generic-advanced-078e99ce-eb46-4324-bd9b-6dc10573508b' {
 # 	menuentry 'Ubuntu, with Linux 4.4.0-178-generic (upstart)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-178-generic-init-upstart-078e99ce-eb46-4324-bd9b-6dc10573508b' {
 # 	menuentry 'Ubuntu, with Linux 4.4.0-178-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-178-generic-recovery-078e99ce-eb46-4324-bd9b-6dc10573508b' {
 # 	menuentry 'Ubuntu, with Linux 4.4.0-21-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-21-generic-advanced-078e99ce-eb46-4324-bd9b-6dc10573508b' {
 # 	menuentry 'Ubuntu, with Linux 4.4.0-21-generic (upstart)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-21-generic-init-upstart-078e99ce-eb46-4324-bd9b-6dc10573508b' {
 # 	menuentry 'Ubuntu, with Linux 4.4.0-21-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-21-generic-recovery-078e99ce-eb46-4324-bd9b-6dc10573508b' {
 # menuentry 'Memory test (memtest86+)' {
 # menuentry 'Memory test (memtest86+, serial console 115200)' {

比如我当前的内核是 Ubuntu，Linux 4.4.0-184-generic。我现在要切换为 Ubuntu，Linux 4.4.0-21-generic

修改配置文件

 // /etc/default/grub
 GRUB_DEFAULT=0
 GRUB_HIDDEN_TIMEOUT=0
 GRUB_HIDDEN_TIMEOUT_QUIET=true
 GRUB_TIMEOUT=10
 GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
 GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
 GRUB_CMDLINE_LINUX=""

GRUB_DEFAULT 配置说明

GRUB_DEFAULT 表示了开机的时候的默认选项（包括二级菜单选项）。

图1

一级菜单 (从 0 开始编号)

 Ubuntu                      对应 0
 Advanced options for Ubuntu 对应 1
 Memory test (memtest86+)    对应 2
 ...

对于二级菜单也是一样的道理，每个菜单项下的子菜单都是从 0 开始编号。那么这里如果我要配置 Advanced options for Ubuntu 下的 Ubuntu，Linux 4.4.0-21-generic，我们的内核顺序就应该是 1>9，这里注意在填写 GRUB_DEFAULT 的时候一定要加上有引号，如:

 GRUB_DEFAULT="Ubuntu，Linux 4.4.0-21-generic"       # 默认一级菜单
 # or
 GRUB_DEFAULT="Advanced options for Ubuntu>Ubuntu，Linux 4.4.0-21-generic"
 # or
 GRUB_DEFAULT="Advanced options for Ubuntu>9"
 # or
 GRUB_DEFAULT="1>Ubuntu，Linux 4.4.0-21-generic"
 # or
 GRUB_DEFAULT="1>9"

更新启动项

 # 更新启动项
 sudo update-grub

这时候会有 WARNING 提示修改 GRUB_DEFAULT 的名称

 Warning: Please don't use old title `Ubuntu, with Linux 4.4.0-179-generic' for GRUB_DEFAULT, use `Advanced options for Ubuntu>Ubuntu, with Linux 4.4.0-179-generic' (for versions before 2.00) or `gnulinux-advanced-078e99ce-eb46-4324-bd9b-6dc10573508b>gnulinux-4.4.0-179-generic-advanced-078e99ce-eb46-4324-bd9b-6dc10573508b' (for 2.00 or later)

根据提示可以使用 “Advanced options for Ubuntu>Ubuntu, with Linux 4.4.0-179-generi” 或者 “gnulinux-advanced-078e99ce-eb46-4324-bd9b-6dc10573508b>gnulinux-4.4.0-179-generic-advanced-078e99ce-eb46-4324-bd9b-6dc10573508b” 将上面的代码放在 GRUB_DEFAULT=’’ 单引号里面

 GRUB_DEFAULT='gnulinux-advanced-078e99ce-eb46-4324-bd9b-6dc10573508b>gnulinux-4.4.0-179-generic-advanced-078e99ce-eb46-4324-bd9b-6dc10573508b'

验证

 # 重启
 sudo reboot

 # 验证
 uname -a