Downgrade Oracle Linux 8 from UEKr7 kernel to UEKr6
I noticed that the latest Oracle Linux 8 U7 Cloud Image from https://yum.oracle.com/oracle-linux-templates.html comes with UEKr7 kernel by default (5.15.0). But this is not yet supported by Oracle Database 19c and it is also missing for example ceph filesystem kernel module.
So here are instructions how to downgrade kernel on OEL8.
First enable UEKr6 tum repository and disable UEKr7 respository. I’m not going to write these instructions, since the copy I have uses our own internal repositories and not public ones.
After that execute:
update file /etc/sysconfig/kernel and set DEFAULTKERNEL=kernel-uek # Install old UEKr6 kernel dnf install kernel-uek # Remove the new UEKr7 kernel rpm -e kernel-uek-core # Regenerate GRUB config grub2-mkconfig -o /boot/grub2/grub.cfg