At Tue, 7 May 2019 05:50:35 -0400 CentOS mailing list centos@centos.org wrote:
On Tue, 7 May 2019 at 04:06, wuzhouhui wuzhouhui14@mails.ucas.ac.cn wrote:
Hi,
Recently, I encountered a interesting phenomenon that CentOS 6.3 running as normal even if I (my colleague, actually) installed a kernel that build for CentOS 7.x (e.g. kernel-3.10.0-327.el7.x86_64.rpm).
I found kernel is mismatch accidentally when I using "uname -r" to check kernel version. So my question is what the harmness we will get if I install a el7 rpm into a el6 system?
Many CentOS-7 packages will not install because they will need dependencies that the EL-6 does not have. The kernel is different because it is mostly self-contained and meant to be parallel installed. In most cases, it should result in an unbootable system because the boot is going to be dracut+systemd bits and the EL-6 has none of that.
And I wonder if the EL7 kernel will even show up as an available kernel. EL7 uses Grub 2 and EL6 uses Grub [1]. *Different* config files. Because (unlike Lilo), grub is not updated in the MBR each time its config is updated (eg installing a new kernel), it is very likely the EL7 kernel rpm install might not touch /boot/grub/grub.conf, since it is expecting to update /boot/grub/grub.cfg instead.
I know that when I installed Ubuntu 18.04 as a *second* OS, that even though the /boot file system is shared between CentOS 6 and Ubuntu 18.04 the Ubuntu 18.04 installer did not touch /boot/grub/grub.conf and installed /boot/grub/grub.cfg along side (I manually reinstalled grub 1 and manually hacked /boot/grub/grub.conf to put the Ubuntu 18.04 boot option in).
Thanks. _______________________________________________ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos