CentOS7 boot kernel 변경하기

CentOS7에서 boot kernel 설정

CentOS7에서는 GRUB2 통하여 아래와 같은 과정을 통해 Boot kernel을 변경

1. 현재 선택 boot kernel 확인

   # grub2-editenv list
   saved_entry=CentOS Linux (3.10.0-1062.4.1.el7.x86_64) 7 (Core)

2. boot kernel 목록 확인

   # cat /etc/grub2.cfg | grep "^menuentry" | cut -d "-" -f1-2
   menuentry 'CentOS Linux (3.10.0-1062.4.1.el7.x86_64) 7 (Core)'
   menuentry 'CentOS Linux (3.10.0-1062.el7.x86_64) 7 (Core)'
   menuentry 'CentOS Linux (0-rescue)

3. 원하는 boot kernel 선택

   # grub2-set-default "CentOS Linux (3.10.0-1062.el7.x86_64) 7 (Core)"

4. 변경된 boot kernel 확인

   # grub2-editenv list
   saved_entry=CentOS Linux (3.10.0-1062.el7.x86_64) 7 (Core)

5. 변경된 boot config 적용

   # grub2-mkconfig -o /boot/grub2/grub.cfg
   Generating grub configuration file ...
   Found linux image: /boot/vmlinuz-3.10.0-1062.4.1.el7.x86_64
   Found linux image: /boot/vmlinuz-3.10.0-1062.el7.x86_64
   Found initrd image: /boot/initramfs-3.10.0-1062.el7.x86_64.img
   Found linux image: /boot/vmlinuz-0-rescue-726b01fcb3d64f63aad7d0aea490aba9
   Found initrd image: /boot/initramfs-0-rescue-726b01fcb3d64f63aad7d0aea490aba9.img
   done

6. system 재부팅

   shutdown -r now