rhel7/oel7上修改默認內核啓動順序的方法

rhel7和 rhel6的默認啓動順序的修改方法，不太同樣，須要使用grub2來修改。具體以下，

好比想修改 Oracle Linux Server, with Linux 3.10.0-123.el7.x86_64做爲默認的啓動項，

--首先找到各菜單項 menuentry
[root@dbserver ~]# cat /boot/grub2/grub.cfg |grep Oracle Linux Server
menuentry 'Oracle Linux Server, with Linux 3.10.0-123.el7.x86_64' --class oracle --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-123.el7.x86_64-advanced-255a4ef5-766f-4992-baaa-a1b3c5488b33' {
menuentry 'Oracle Linux Server, with Unbreakable Enterprise Kernel 3.8.13-35.3.1.el7uek.x86_64' --class oracle --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.8.13-35.3.1.el7uek.x86_64-advanced-255a4ef5-766f-4992-baaa-a1b3c5488b33' {
menuentry 'Oracle Linux Server, with Linux 0-rescue-171210b6f8734bbe81074e4c0306c0f3' --class oracle --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-0-rescue-171210b6f8734bbe81074e4c0306c0f3-advanced-255a4ef5-766f-4992-baaa-a1b3c5488b33' {
if [ "x$default" = 'Oracle Linux Server, with Linux 3.10.0-123.el7.x86_64' ]; then default='Advanced options for Oracle Linux Server>Oracle Linux Server, with Linux 3.10.0-123.el7.x86_64'; fi;

--設置Oracle Linux Server, with Linux 3.10.0-123.el7.x86_64做爲默認的啓動項
[root@dbserver ~]# grub2-set-default "Oracle Linux Server, with Linux 3.10.0-123.el7.x86_64"

 

--驗證默認啓動項
[root@dbserver ~]# grub2-editenv list
saved_entry=Oracle Linux Server, with Linux 3.10.0-123.el7.x86_64

--自動生成GRUB2配置文件
[root@dbserver ~]# grub2-mkconfig -o /boot/grub2/grub.cfg

下次重啓，就會默認自動啓動第一項了。