RedhatKernelPackage - spack.org/wiki

Buildng a Custom Redhat Kernel RPM

This howto may also be useful for modifying other RedhatLinux packages as well. Much thanks to AaronCaskey for writing the original version of this.

Contents

Buildng a Custom Redhat Kernel RPM

Download the Source RPM

Download the official RedhatLinux SRPM (remember to check the updates directory for the latest version)
http://mirror.aarnet.edu.au/pub/linux/redhat/updates/9/en/os/SRPMS/
Install the source RPM into /usr/src/redhat/SOURCES:
```
# rpm -Uvh kernel-<version>.src.rpm
```

Patch the Kernel

The Redhat Way is to leave the original source alone and only make changes via patching, it's a good idea to stick to that.

Creating Patches

The latest version of AutoMount 4.1.0 comes with a patch for the Redhat kernel (for ghosting support) so for that we don't need this step. However if you need to make changes and don't have a patch here's an (untested) example of how to make one:

Find the .spec file for the newly installed kernel sources:
```
# cd /usr/src/redhat/SPECS
```
Prepare the sources for building (-bp means "build prep")
```
# rpmbuild -bp kernel-2.4.spec
```
The prepared source should now be in the BUILD directory, make a copy of it before you make any changes.
```
# cp -a /usr/src/redhat/BUILD /tmp/
```
Now make what ever changes you require to the kernel sources, when you are done you can make a patch by diff'ing your copy against the modified original. The generated patch is what you use in the next step.
```
# diff -ur ????? > /tmp/kernel-custom-adam.patch
```

Applying Patches

Copy any desired patches into /usr/src/redhat/SOURCES:

# cp /tmp/autofs4-2.4.20-redhat.patch /usr/src/redhat/SPECS

It's a really good idea to edit the release tag in the spec file. If you add a site tag and build number then you'll be able to figure out which boxes are running which version of a custom kernel:
```
%define release 30.spack.01
```
Now add patch to the list of patches in the spec file (I had to put the autofs patch at the end to avoid it conflicting with another patch):
```
Patch11040: autofs4-2.4.20-redhat.patch
```
And add the patch, and any required options to patch, to the application section of the spec file:
```
"%patch11040 -p1"
```
Test the patching process, your patch should show up in the output. If it generates errors you need to figure out what's wrong and fix it before you continue.
```
# rpmbuild -bp kernel-2.4.20.spec
```

Compiling the Kernel

Assuming everthing went well you should now be ready to build a new kernel:

Change into the SPECS directory:
```
# cd /usr/src/redhat/SPECS
```

Build the kernel packages you require. You may want to specify which targets you require inux system can build kernels for muliple targets:

# rpmbuild -ba kernel-2.4.20.spec                 # builds the i386 kernel, sources, docs etc
# rpmbuild -bb --target=i686 kernel-2.4.20.spec   # to build the bigmem and other i686 kernels

When it's finished building you should have these kernels:

# ls /usr/src/redhat/*RPMS/*
/usr/src/redhat/SRPMS:
        kernel-2.4.20-30.spack.01.src.rpm
/usr/src/redhat/RPMS/i386:
        kernel-2.4.20-30.spack.01.i386.rpm
        kernel-doc-2.4.20-30.spack.01.i386.rpm
        kernel-BOOT-2.4.20-30.spack.01.i386.rpm  
        kernel-source-2.4.20-30.spack.01.i386.rpm
/usr/src/redhat/RPMS/i686:
        kernel-2.4.20-30.spack.01.i686.rpm
        kernel-bigmem-2.4.20-30.spack.01.i686.rpm
        kernel-smp-2.4.20-30.spack.01.i686.rpm

Installing the New Kernel

Install your new kernel RPM the same way you would for anything else:

# rpm -Uvh kernel-bigmem-2.4.20-30.spack.01.i686.rpm

Modern versions of RedhatLinux will update the GrubBootloader automatically, if you use the LiloBootloader you'll need to update your /etc/lilo.conf manually.

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