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resolved – switching from Unbreakable Enterprise Kernel Release 2(UEKR2) to UEKR3 on Oracle Linux 6

November 24th, 2014

As we can see from here, the available kernels include the following 3 for Oracle Linux 6:

3.8.13 Unbreakable Enterprise Kernel Release 3 (x86_64 only)
2.6.39 Unbreakable Enterprise Kernel Release 2**
2.6.32 (Red Hat compatible kernel)

On one of our OEL6 VM, we found that it's using UEKR2:

[root@testbox aime]# cat /etc/issue
Oracle Linux Server release 6.4
Kernel \r on an \m

[root@testbox aime]# uname -r
2.6.39-400.211.1.el6uek.x86_64

So how can we switch the kernel to UEKR3(3.8)?

If your linux version is 6.4, first do a "yum update -y" to upgrade to 6.5 and uppper, and then reboot the host, and follow steps below.

[root@testbox aime]# ls -l /etc/grub.conf
lrwxrwxrwx. 1 root root 22 Aug 21 18:24 /etc/grub.conf -> ../boot/grub/grub.conf

[root@testbox aime]# yum update -y

If your linux version is 6.5 and upper, you'll find /etc/grub.conf and /boot/grub/grub.conf are different files(for yum update one. If your host is OEL6.5 when installed, then /etc/grub.conf should be softlink too):

[root@testbox ~]# ls -l /etc/grub.conf
-rw------- 1 root root 2356 Oct 20 05:26 /etc/grub.conf

[root@testbox ~]# ls -l /boot/grub/grub.conf
-rw------- 1 root root 1585 Nov 23 21:46 /boot/grub/grub.conf

In /etc/grub.conf, you'll see entry like below:

title Oracle Linux Server Unbreakable Enterprise Kernel (3.8.13-44.1.3.el6uek.x86_64)
root (hd0,0)
kernel /vmlinuz-3.8.13-44.1.3.el6uek.x86_64 ro root=/dev/mapper/vg01-lv_root rd_LVM_LV=vg01/lv_root rd_NO_LUKS rd_LVM_LV=vg01/lv_swap LANG=en_US.UTF-8 KEYTABLE=us console=hvc0 rd_NO_MD SYSFONT=latarcyrheb-sun16 rd_NO_DM rhgb quiet
initrd /initramfs-3.8.13-44.1.3.el6uek.x86_64.img

What you'll need to do is just copying the entries above from /etc/grub.conf to /boot/grub/grub.conf(make sure /boot/grub/grub.conf not be a softlink, else you may met error "Boot loader didn't return any data"), and then reboot the VM.

After rebooting, you'll find the kernel is now at UEKR3(3.8).

PS:

If you find the VM is OEL6.5 and /etc/grub.conf is a softlink to /boot/grub/grub.conf, then you could do the following to upgrade kernel to UEKR3:

1. add the following lines to /etc/yum.repos.d/public-yum-ol6.repo:

[public_ol6_UEKR3]
name=UEKR3 for Oracle Linux 6 ($basearch)
baseurl=http://public-yum.oracle.com/repo/OracleLinux/OL6/UEKR3/latest/$basearch/
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-oracle
gpgcheck=1
enabled=1

2. List and install UEKR3:

[root@testbox aime]# yum list|grep kernel-uek|grep public_ol6_UEKR3
kernel-uek.x86_64 3.8.13-44.1.5.el6uek public_ol6_UEKR3
kernel-uek-debug.x86_64 3.8.13-44.1.5.el6uek public_ol6_UEKR3
kernel-uek-debug-devel.x86_64 3.8.13-44.1.5.el6uek public_ol6_UEKR3
kernel-uek-devel.x86_64 3.8.13-44.1.5.el6uek public_ol6_UEKR3
kernel-uek-doc.noarch 3.8.13-44.1.5.el6uek public_ol6_UEKR3
kernel-uek-firmware.noarch 3.8.13-44.1.5.el6uek public_ol6_UEKR3
kernel-uek-headers.x86_64 3.8.13-26.2.4.el6uek public_ol6_UEKR3

[root@testbox aime]# yum install -y kernel-uek* --disablerepo=* --enablerepo=public_ol6_UEKR3

3. Reboot

Good Luck!


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