Running older kernel version, yum sees no new one

jonaskellens · 06-26-2010, 03:26 AM

Hello.

I'm running a Xen VDS from a hosting company.
I'm trying to update the kernel, because the one that is running is rather "old" :

Code:

bash-3.2# uname -a
Linux vps.hosting.net 2.6.18-128.4.1.el5xen #1 SMP Tue Aug 4 20:51:12 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux

I try to update the kernel with yum, but fail :

Code:

bash-3.2# yum update
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * addons: centos.mirror.transip.nl
 * base: centos.mirror.transip.nl
 * extras: centos.mirror.transip.nl
 * rpmforge: fr2.rpmfind.net
 * updates: centos.mirror.transip.nl
Setting up Update Process
No Packages marked for Update

Code:

bash-3.2# yum update kernel
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * addons: centos.mirror.transip.nl
 * base: centos.mirror.transip.nl
 * extras: centos.mirror.transip.nl
 * rpmforge: fr2.rpmfind.net
 * updates: centos.mirror.transip.nl
Setting up Update Process
No Packages marked for Update

Code:

bash-3.2# yum search kernel
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * addons: centos.mirror.transip.nl
 * base: centos.mirror.transip.nl
 * extras: centos.mirror.transip.nl
 * rpmforge: fr2.rpmfind.net
 * updates: centos.mirror.transip.nl
<snip>
kernel.x86_64 : The Linux kernel (the core of the Linux operating system)
kernel-debug.x86_64 : The Linux kernel compiled with extra debugging enabled.
kernel-debug-devel.x86_64 : Development package for building kernel modules to match the kernel.
kernel-devel.x86_64 : Development package for building kernel modules to match the kernel.
kernel-doc.noarch : Various documentation bits found in the kernel source.
kernel-headers.x86_64 : Header files for the Linux kernel for use by glibc
kernel-xen.x86_64 : The Linux kernel compiled for Xen VM operations
kernel-xen-devel.x86_64 : Development package for building kernel modules to match the kernel.
kerneloops.x86_64 : Tool to automatically collect and submit kernel crash signatures
<snip>

So where to get a more up to date kernel ??

smoker · 06-26-2010, 06:10 AM

You won't get one through yum. RHEL5 only uses 2.6.18 by default. See this post and also bear in mind that RH update the kernel with patches, but you usually only get minor change in the version number.

Quote:

On the other hand in terms of the distribution's basic software – such as the Linux kernel or the glibc – Red Hat tends to avoid major jumps to new versions. The RHEL 5.5 kernel, like that of RHEL 5.0, is therefore based on the rather dusted-down kernel version 2.6.18. However, the Red Hat kernel does differ in many ways from the Linux kernel 2.6.18 available at kernel.org, because the Red Hat developers have already integrated a vast number of advancements from current versions of the Linux kernel. This includes many drivers for recent hardware, as the drivers included in Linux 2.6.18 are unsuitable or insufficient for many modern systems.

http://www.h-online.com/open/feature...-5-969097.html

knudfl · 06-26-2010, 06:59 AM

Quote:

bash-3.2# uname -a
Linux vps.hosting.net

This indicates a "special" from your provider. ?
Kernel updates might be blocked. ( For good reasons.)
Did you ask the provider ? ?

Kernel updates can be excluded in /etc/yum.conf :
exclude=kernel*
... which excludes all packages starting with : "kernel".

By the way, the latest is : kernel-xen-2.6.18-194.el5.x86_64
Lots of updates from 2.6.2x.x and 2.6.3x.x are included in these
2.6.18 el5 kernels, also in the version, you have installed.
Please read %changelog in the file kernel.spec
...

smoker · 06-26-2010, 07:52 AM

Quote:

Originally Posted by knudfl

This indicates a "special" from your provider. ?
Kernel updates might be blocked. ( For good reasons.)
Did you ask the provider ? ?

???

That's the default hostname. It implies nothing about the kernel version. If it was a shared server it might be relevant, but on a vps anything should be possible within the hardware limits for the virtualisation software.

knudfl · 06-26-2010, 08:25 AM

@ smoker post # 4 : Sorry, I wasn't that alert.

There may be another reason for no updating to "build 194".
As you can see, the naming has changed ...
kernel-2.6.18-128.4.1.el5xen ( CentOS 5.4 name )
kernel-xen-2.6.18-194.el5 ( CentOS 5.5 name )

..

jonaskellens · 06-26-2010, 09:13 AM

Quote:

Originally Posted by knudfl

kernel-2.6.18-128.4.1.el5xen ( CentOS 5.4 name )
kernel-xen-2.6.18-194.el5 ( CentOS 5.5 name )

Webmin tells me I'm running CentOS 5.5 and that there are no updates :

Operating system CentOS Linux 5.5
Webmin version 1.510
Kernel and CPU Linux 2.6.18-128.4.1.el5xen on x86_64

smoker · 06-26-2010, 09:19 AM

Have you tried yum install kernel-xen ?

jonaskellens · 06-26-2010, 10:07 AM

Quote:

Originally Posted by smoker

Have you tried yum install kernel-xen ?

That was not such a bad idea, look :

Code:

bash-3.2# yum install kernel-xen
<snip>
Package kernel-xen-2.6.18-194.3.1.el5.x86_64 already installed and latest version
Nothing to do
bash-3.2# uname -a
Linux vps2301.xlshosting.net 2.6.18-128.4.1.el5xen #1 SMP Tue Aug 4 20:51:12 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux

I did not know I had several kernels installed :

Code:

bash-3.2# ls -l /usr/src/kernels/
total 40
drwxr-xr-x 19 root root 4096 Aug 18  2009 2.6.18-128.4.1.el5-x86_64
drwxr-xr-x 19 root root 4096 Aug 18  2009 2.6.18-128.4.1.el5-xen-x86_64
lrwxrwxrwx  1 root root   29 Aug 18  2009 2.6.18-128.4.1.el5xen-x86_64 -> 2.6.18-128.4.1.el5-xen-x86_64
drwxr-xr-x 19 root root 4096 Jan  9 00:27 2.6.18-164.10.1.el5-x86_64
drwxr-xr-x 19 root root 4096 Jan  9 00:27 2.6.18-164.10.1.el5-xen-x86_64
lrwxrwxrwx  1 root root   30 Jan  9 00:27 2.6.18-164.10.1.el5xen-x86_64 -> 2.6.18-164.10.1.el5-xen-x86_64
drwxr-xr-x 19 root root 4096 Jan 21 03:41 2.6.18-164.11.1.el5-x86_64
drwxr-xr-x 19 root root 4096 Jan 21 03:41 2.6.18-164.11.1.el5-xen-x86_64
lrwxrwxrwx  1 root root   30 Jan 21 03:41 2.6.18-164.11.1.el5xen-x86_64 -> 2.6.18-164.11.1.el5-xen-x86_64
drwxr-xr-x 19 root root 4096 Apr 19 10:06 2.6.18-164.15.1.el5-x86_64
drwxr-xr-x 19 root root 4096 Apr 19 10:06 2.6.18-164.15.1.el5-xen-x86_64
lrwxrwxrwx  1 root root   30 Apr 19 10:06 2.6.18-164.15.1.el5xen-x86_64 -> 2.6.18-164.15.1.el5-xen-x86_64
drwxr-xr-x 19 root root 4096 Jun  3 15:08 2.6.18-194.3.1.el5-x86_64
drwxr-xr-x 19 root root 4096 Jun  3 15:08 2.6.18-194.3.1.el5-xen-x86_64
lrwxrwxrwx  1 root root   29 Jun  3 15:08 2.6.18-194.3.1.el5xen-x86_64 -> 2.6.18-194.3.1.el5-xen-x86_64

I guess I just have to point to the right kernel ??

Code:

bash-3.2# cat /boot/grub/menu.lst 
# grub.conf generated by anaconda
#boot=/dev/sda
default=0
timeout=10
splashimage=(hd0,0)/boot/grub/splash.xpm.gz
hiddenmenu
title CentOS (2.6.18-128.4.1.el5xen)
        root (hd0,0)
        kernel /boot/vmlinuz-2.6.18-128.4.1.el5xen ro root=/dev/sda1 console=xvc0
        initrd /boot/initrd-2.6.18-128.4.1.el5xen.img

Code:

bash-3.2# ls -l /boot/ | grep 194
-rw-r--r-- 1 root root   66891 May 13 19:38 config-2.6.18-194.3.1.el5
-rw-r--r-- 1 root root   66552 May 13 20:21 config-2.6.18-194.3.1.el5xen
-rw------- 1 root root 2486803 Jun  3 15:09 initrd-2.6.18-194.3.1.el5.img
-rw------- 1 root root 2495432 Jun  3 15:09 initrd-2.6.18-194.3.1.el5xen.img
-rw-r--r-- 1 root root  112667 May 13 19:39 symvers-2.6.18-194.3.1.el5.gz
-rw-r--r-- 1 root root  112211 May 13 20:21 symvers-2.6.18-194.3.1.el5xen.gz
-rw-r--r-- 1 root root 1242305 May 13 19:38 System.map-2.6.18-194.3.1.el5
-rw-r--r-- 1 root root 1208650 May 13 20:21 System.map-2.6.18-194.3.1.el5xen
-rw-r--r-- 1 root root 1954652 May 13 19:38 vmlinuz-2.6.18-194.3.1.el5
-rw-r--r-- 1 root root 2046773 May 13 20:21 vmlinuz-2.6.18-194.3.1.el5xen
-rw-r--r-- 1 root root  417383 May 13 19:01 xen.gz-2.6.18-194.3.1.el5
-rwxr-xr-x 1 root root  969816 May 13 21:15 xen-syms-2.6.18-194.3.1.el5

So to which vmlinuz and initrd file do I point best ???

smoker · 06-26-2010, 10:59 AM

I guess the ones with the same version numbers. You could put them all into the grub menu, making sure to match the versions for each then you can try booting the xen or non-xen and see which performs better. Of course, if it's a remote server, I would suggest changing the default to whichever kernel you want to boot.
The first in the list is 0, then 1, then 2 etc etc.

Make them look like the existing one :

Code:

title CentOS (2.6.18-194.3.1.el5xen)
        root (hd0,0)
        kernel /boot/vmlinuz-2.6.18-194.3.1.el5xen ro root=/dev/sda1 console=xvc0
        initrd /boot/initrd-2.6.18-194.3.1.el5xen.img

same for the non-xen kernel

if you leave the existing kernel entry and put the one I posted after it then change the default to default=1 it will boot this kernel.

I'm a bit concerned that grub wasn't auto updated when the kernels were installed.

jonaskellens · 06-26-2010, 12:13 PM

Quote:

Originally Posted by smoker

I'm a bit concerned that grub wasn't auto updated when the kernels were installed.

I think my Hosting company has just installed the kernels in /usr/src/kernels and leave the rest to my decision.

I have a sort of remote view of the VDS so I can see the grub splash menu to select a kernel to boot.

I will make el5xen the default. This seems the closest to a "Xen-domU compatible kernel".

knudfl · 06-26-2010, 12:35 PM

One comment : There are no kernels in /usr/src/kernels/.
Only the source code.

'kernel' : /boot/vmlinuz-<version>
And the associated modules are in /lib/modules/<version>

..

smoker · 06-26-2010, 01:42 PM

Quote:

Originally Posted by jonaskellens

I have a sort of remote view of the VDS so I can see the grub splash menu to select a kernel to boot.

That's ok if you are there to choose it. If for whatever reason the box goes down, you want your chosen default to come back up. So specify it in the grub menu.