CentOS 7
- 查看系統(tǒng)內(nèi)部有多少個(gè)內(nèi)核：
cat /boot/grub2/grub.cfg |grep menuentry
- 配置從默認(rèn)內(nèi)核啟動(dòng)救氯，下面命令的內(nèi)核名稱根據(jù)系統(tǒng)內(nèi)部查到的實(shí)際名稱來(lái)替換：
grub2-set-default “CentOS Linux (4.4.138) 7 (Core)”
- 驗(yàn)證是否配置成功：
grub2-editenv list
Ubuntu16.04
- 0.環(huán)境準(zhǔn)備
Ubuntu16.04漩符，內(nèi)核版本4.10.0奶稠，新內(nèi)核版本4.4.137 - 1.修改grub配置文件
編輯/etc/default/grub文件赐纱，將其中的GRUB_DEFAULT的值修改為saved
sudo gedit /etc/default/grub
- 2.查看系統(tǒng)內(nèi)部已安裝的內(nèi)核
sudo cat /boot/grub/grub.cfg | grep menuentry
選擇新的默認(rèn)內(nèi)核幕随，內(nèi)核名稱在menuentry后的雙引號(hào)內(nèi)茅逮，例如上述命令顯示結(jié)果如下言缤，從其中選擇Ubuntu, with Linux 4.4.137作為新的啟動(dòng)內(nèi)核
menuentry 'Ubuntu, with Linux 4.10.0-28-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.10.0-28-generic-advanced-a58882f8-c86d-4817-8517-0b846a106892' {
menuentry 'Ubuntu, with Linux 4.10.0-28-generic (upstart)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.10.0-28-generic-init-upstart-a58882f8-c86d-4817-8517-0b846a106892' {
menuentry 'Ubuntu, with Linux 4.10.0-28-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.10.0-28-generic-recovery-a58882f8-c86d-4817-8517-0b846a106892' {
menuentry 'Ubuntu, with Linux 4.4.137' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.137-advanced-a58882f8-c86d-4817-8517-0b846a106892' {
menuentry 'Ubuntu, with Linux 4.4.137 (upstart)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.137-init-upstart-a58882f8-c86d-4817-8517-0b846a106892' {
menuentry 'Ubuntu, with Linux 4.4.137 (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.137-recovery-a58882f8-c86d-4817-8517-0b846a106892' {
menuentry 'Ubuntu, with Linux 4.4.137.old' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.137.old-advanced-a58882f8-c86d-4817-8517-0b846a106892' {
menuentry 'Ubuntu, with Linux 4.4.137.old (upstart)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.137.old-init-upstart-a58882f8-c86d-4817-8517-0b846a106892' {
menuentry 'Ubuntu, with Linux 4.4.137.old (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.137.old-recovery-a58882f8-c86d-4817-8517-0b846a106892'
- 2.配置從默認(rèn)內(nèi)核啟動(dòng)
sudo grub-set-default xxx
其中xxx為選定的新內(nèi)核的名稱，例如此處的具體命令為
sudo grub-set-default "Ubuntu, with Linux 4.4.137"
更新grub配置
sudo update-grub
但Ubuntu16.04此處會(huì)報(bào)warning,warning信息如下
Warning: Please don't use old title `Ubuntu, with Linux 4.4.137' for GRUB_DEFAULT, use `Advanced options for Ubuntu>Ubuntu, with Linux 4.4.137' (for versions before 2.00) or `gnulinux-advanced-a58882f8-c86d-4817-8517-0b846a106892>gnulinux-4.4.137-advanced-a58882f8-c86d-4817-8517-0b846a106892' (for 2.00 or later)
warning中推薦使用Advanced options for Ubuntu>Ubuntu, with Linux 4.4.137导而，因此使用推薦的啟動(dòng)項(xiàng)（雙引號(hào)內(nèi)的內(nèi)容）修改默認(rèn)啟動(dòng)內(nèi)核忱叭，例如
sudo grub-set-default "Advanced options for Ubuntu>Ubuntu, with Linux 4.4.137"
PS.在本人的測(cè)試中發(fā)下如果不使用Advanced選項(xiàng)，重啟后仍為舊內(nèi)核今艺；每次grub-set-default后都需要update-grub
- 3.重啟驗(yàn)證
sudo reboot
uname -r
