First, set yum repo according to OS version (skip this if you already have yum repo configured)
cd /etc/yum.repos.d; mkdir bak;unalias mv;mv -f *.repo bak;uname -r|grep -q el5 && curl 'http://public-yum.oracle.com/public-yum-el5.repo' -o public-yum-el5.repo;uname -r|grep -q el6 && curl 'http://public-yum.oracle.com/public-yum-ol6.repo' -o public-yum-ol6.repo;uname -r|grep -q el7 && curl 'http://yum.oracle.com/public-yum-ol7.repo' -o public-yum-el7.repo;
Now edit yum repo to specify UEK Release to upgrade to (search "UEK" in yum file), take OEL6 yum file for example
ol6_UEK_latest - enable this will upgrade kernel to latest kernel version of current release, e.g. from 2.6.39-200.xxx to 2.6.39-400.xxx
ol6_UEKR3_latest - will upgrade from 2.xxx to 3.xxx
ol6_UEKR4 - will upgrade from 2.xxx/3.xxx to 4.xxx
After above, use yum list to confirm the kernel that will be upgraded to:
yum list|grep kernel-uek
Do the upgrade now
yum update kernel-uek*
Or you can specify version to upgrade to, e.g. to upgrade OEL linux kernel to 2.6.39-400.300.2.el6uek:
yum update kernel-uek*2.6.39-400.300.2.el6uek*
Check to see if the new kernel is in /boot/grub/grub.conf. If it's in /etc/grub.conf, but NOT in /boot/grub/grub.conf, then you need do below:
cp /boot/grub/grub.conf /boot/grub/grub.conf.bak;cp /etc/grub.conf /etc/grub.conf.bak
cat /etc/grub.conf > /boot/grub/grub.conf
rm /etc/grub.conf
ln -s /boot/grub/grub.conf /etc/grub.conf