kernel upgrade

[skt_skt]

what is the importance of upgrading the kernel-headers package when we upgrade the kernel&&kernel-utils.

My approach is to upgrade the kernel and kernel-util only till now.

[Ivan Ferreira]

You should maintain the same versions for the kernel and kernel-headers.

The header files define structures and constants that are needed for building most standard programs.

[skt_skt]

i always install the kernel(not upgrade) which enables me to switch back to the old kernel.

what is the effect of upgrading the kernel-headers with respect to the said kernel switching facilcity?.

[Stuart Browne · Accepted solution]

The reason for updating the kernel-headers package is to allow you to compile things against the newest version of th ekernel settings.

If you aren't compiling things, it's a non-issue.

If you are compiling things, then pretty much any version will do, unless you're doing cutting edge kernel development where the latest settings/tweaks really count.

If you're in an Enterprise environment, this is highly doubtful.

[sandeep mathur]

The kernel-headers package contains the C header files for this Linux kernel. You may need this package to build a program from source.


it helps in user space programs.

[skt_skt]

can the following be installed online w/o affecting the server? Did any one try this?

Kernel-headers
Kernel-source

In some cases i need to install them and some cases it will be an updated to match the running kernel.

[~sesh]

As far as I know kernel compilation can be done when the system is in operation. In fact you need Linux running to be able to compile the kernel.

Once you have got the required kernel source, save it to /usr/src (or any other directory to make sense). Use tar zxvf to unzip the file. Use the make menuconfig command in the directory /usr/src/Linux to start the process.

Once the kernel is compiled, you need to create an image of it and add entries to LILO or GRUB to boot from it.

There are many sites like the one I've provided, with detailed information about how to compile the kernel & install it.

http://linuxplanet.com/linuxplanet/tutorials/202/1/

Hope this helps.

[~sesh]

One thing I forgot to mention, the process of kernel compilation is a resource intensive task & could take some time. Although it can be done while server is live, it may affect the performance of the server.

There is also a very exhaustive guide to upgrading the kernel on the RedHat web site.
http://www.redhat.com/support/resources/howto/kernel-upgrade/

This also would involve a lot of work & ideally should be performed during a maintenance window or during "lean hours".

[skt_skt]

let me be a little more clear on my scenario

I have already updated the kernel and kernel. But not the respective kernel-source and kernel-headers. I prefer to update the source and headers w/o an ouatge.

Now i am getting some errors while installing third party drivers.

for example

ERROR - The ASM driver failed to build.
Most likely there is a problem with the kernel
headers on your machine, or with the
/lib/modules/2.4.21-47.ELsmp/build symlink not pointing to the
correct kernel source tree.

]# ./lpfc-install
Emulex LPFC Driver Installer Version 1.4.1.10
Determining distribution type and kernel version ...
Checking for old Emulex driver ...
Looking for kernel source ...
Looking for compilers ...

RPM cannot be installed: kernel source package is required.

./lpfc-install was unable to successfully build and load a driver.
Please install the appropriate kernel source code and then re-run
./lpfc-install

[James R. Ferguson]

Hi:

As far as I know, you can update your kernel-headers and kernel-source packages online, while operations are running normally. Afterall, this is source code not executables.

Once done, you should be able to compile your third-party drivers since the requisite C-headers will match the *running* kernel which you previously updated.

Regards!

...JRF...