本文不再更新，可能存在内容过时的情况，实时更新请移步原文地址：CENTOS 7更换系统启动默认内核；

环境：

• CentOS Linux release 7.6.1810 (Core) ；

1.查看当前默认启动内核

[[email protected] ~]$ grub2-editenv list
grub2-editenv: error: cannot open `/boot/grub2/grubenv.new': Permission denied.
[[email protected] ~]$ sudo grub2-editenv list
[sudo] password for inspur: 
saved_entry=CentOS Linux (3.10.0-957.21.3.el7.x86_64) 7 (Core)
[[email protected] ~]$

1. 查看所有内核

[[email protected] ~]$ sudo cat /boot/grub2/grub.cfg | grep menuentry
if [ x"${feature_menuentry_id}" = xy ]; then
  menuentry_id_option="--id"
  menuentry_id_option=""
export menuentry_id_option
menuentry 'CentOS Linux (3.10.0-957.21.3.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-862.el7.x86_64-advanced-1ef88ad8-4275-4ceb-9d7f-80abefd6a4c2' {
menuentry 'CentOS Linux (3.10.0-862.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-862.el7.x86_64-advanced-1ef88ad8-4275-4ceb-9d7f-80abefd6a4c2' {
menuentry 'CentOS Linux (0-rescue-396035e748534ed49bfde6ab589c7cbe) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-0-rescue-396035e748534ed49bfde6ab589c7cbe-advanced-1ef88ad8-4275-4ceb-9d7f-80abefd6a4c2' {
[[email protected] ~]$

3.设置新的启动内核

[[email protected] ~]$ sudo grub2-set-default 'CentOS Linux (3.10.0-862.el7.x86_64) 7 (Core)'
[[email protected] ~]$

4.验证启动内核

[[email protected] ~]$ sudo grub2-editenv list
saved_entry=CentOS Linux (3.10.0-862.el7.x86_64) 7 (Core)
[[email protected] ~]$

本文不再更新，可能存在内容过时的情况，实时更新请移步原文地址：CENTOS 7更换系统启动默认内核；