Changes

Jump to: navigation, search

Kernel build

1,946 bytes added, 08:40, 26 December 2015
Marked this version for translation
<translate>
<!--T:1-->
This FAQ will help you in case you want to apply some patches to the kernel on your own or rebuild it from sources.
On RPM based distros such as RedHat Enterprise Linux/CentOS, Fedora Core or SUSE one can simpy rebuild kernel from SRPM,.for For other distros it is required to install sources, build and install kernel manually. The below are given the details for both cases.
== Rebuilding kernel from SRPM ==<!--T:2-->
=== Download Find out $TOPDIR ===<!--T:3-->Source RPM for OpenVZ kernel '''Note''': paths in some of the commands below include $TOPDIR, which is distribution-dependent and can be download from further redefined by user. To find out the official downloads at http://openvz.org/download/kernel/.Beta versions proper location of kernels for different OS distributions can be also found at http$TOPDIR on your system, issue this command://openvz.org/download/beta/.
<!--T:4-->TOPDIR=$(rpm --eval "%{_topdir}"); echo $TOPDIR === Download === <!--T:5-->Source RPMS for different OpenVZ kernel branches can be downloaded from http://openvz.org/download/kernel/. You can also access http://download.openvz.org/kernel/ directly, or use one of the [[download mirrors|mirrors]]. === Installation ===<!--T:6-->
Install the downloaded SRC RPM with the following command:
<pre>
# rpm -ihv ovzkernel-2.6.16-026test012.1.src.rpm
</pre>
<!--T:7--># rpm -ihv ovzkernel-{{kver}}-{{krel}}.src.rpm <!--T:8-->After successfull installation , you can usually find kernel sources in /usr/src/<distrocode>$TOPDIR/SOURCES/</code>and kernel spec file (<code>kernel-ovz.spec</code>) in /usr/src/<distrocode>$TOPDIR/SPECS, where <distro/code> is your distribution-specific directory.For example, for RedHat based distros it is 'redhat', for SUSE it is 'packages'.
=== Adding your own patches ===<!--T:9-->To modify the kernel one needs just to add specific patches to the kernel spec file and put this patch into <code>$TOPDIR/SOURCES </code> directory. <!--T:10-->
Put your patch into SOURCES directory with the following command:
<pre>
# cp <patch> /usr/src/<distro>/SOURCES/
</pre>
<!--T:11--># cp <patch> $TOPDIR/SOURCES/ <!--T:12-->Then open spec file /usr/src/<distrocode>$TOPDIR/SPECS/kernel-ovz.spec </code> in the editor and add the following lines:  <pre!--T:13-->Patch10000Patch100000: <patch-name> </pre!--T:14-->
and
  <pre!--T:15-->%patch10000 patch100000 -p1 </pre!--T:16-->
in appropriate places where similar text lines are.
=== Building RPMs Adjust kernel version ===<!--T:17-->Before rebuilding the kernel make sure that you adjusted the kernel version in <code>kernel-ovz.spec</code>.
This will help you to distinguish binaries then from already existing kernels
(or from the official OpenVZ kernels). To do so, edit /usr/src/the <distrocode>$TOPDIR/SPECS/kernel-ovz.spec </code> file and replace the following line:  <pre!--T:18-->
%define ksubrelease 1
</pre>
with
<pre>
%define ksubrelease 1-my.kernel.v1
</pre>
<!--T:19-->
with something like
 
<!--T:20-->
%define ksubrelease 1my.kernel.v1
To rebuild === Modifying configs === <!--T:21-->If you want to modify the kernel type config, you need to do the following commands then:<pre>before you continue with [[# cd /usr/src/<distro>/SPECS# rpmbuild -ba --target=i686 kernel-ovzBuilding RPMs|the next step]].spec</pre>
After successfull <!--T:22--># cd $TOPDIR/SPECS # rpmbuild -bp kernel compilation binary RPMs can be found at -ovz.spec # cd $TOPDIR/usrBUILD/src/<distro>/RPMSkernel-{{kver}}/i686linux-{{kver}}
== Rebuilding <!--T:23-->'''Note''': Make sure all OpenVZ related options are set. See [[kernel from sources ==configuration]]
<!--T:24-->There you will find the configuration files in the subdirectory <code>config/*.config</code>. Copy the one you want to modifiy to <code>$TOPDIR/BUILD/kernel-{{kver}}/linux-{{kver}}/.config</code>. Then you can do a make menuconfig or something similar to adjust the kernel configuration. Note that some kernel configuration issues are described at [[kernel configuration]]. <!--T:25-->Next, copy <code>$TOPDIR/BUILD/kernel-{{kver}}/linux-{{kver}}/.config</code> to the <code>$TOPDIR/SOURCES</code> directory, but use the corresponding file name in the target directory. === Building RPMs === <!--T:26-->To rebuild the kernel, type the following commands:  <!--T:27--># cd $TOPDIR/SPECS # rpmbuild -ba --target=i686 kernel-ovz.spec <!--T:28-->After successfull kernel compilation binary RPMs can be found at <code>$TOPDIR/RPMS/i686</code>. == Rebuilding kernel from sources == <!--T:29--> === Download ===<!--T:30-->
To compile OpenVZ linux kernel one need to download the original linux kernel sources and OpenVZ patches for it.
<!--T:31-->Linux kernel can be found at [http://www.kernel.org/kernel.org], e.g. 2.6.16 {{kver}} kernel can be downloaded from [http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.16{{kver}}.tar.bz2 from here].
<!--T:32-->Appropriate OpenVZ patches for this kernel version can be found at <nowiki>http://openvz.org/download/kernel/branches/<branch>/<version>/patches/</nowiki>. For example, e.g. at the moment there is a patch [http://download.openvz.org/betakernel/kernelbranches/{{kver}}/026test012.1{{krel}}/patches/patch-026test012ovz{{krel}}-combined.gz patch-026test012ovz{{krel}}-combined.gz] available. <!--T:33-->Kernel configs are also avaialble available at OpenVZ download site. Most usually frequently SMP config is used, so lets let's download [http://download.openvz.org/betakernel/kernelbranches/{{kver}}/026test012.1{{krel}}/configs/kernel-2.6.16-026test012{{kver}}-i686-smp.config.ovz kernel-2.6.16-026test012{{kver}}-i686-smp.config.ovz]
for this example.
=== Building Prepare ===<!--T:34-->
First, extract the kernel sources from archive:
<pre>
# tar vjxf linux-2.6.16.tar.bz2
# cd linux-2.6.16
</pre>
<!--T:35-->
# tar vjxf linux-{{kver}}.tar.bz2
# cd linux-{{kver}}
 
<!--T:36-->
Apply OpenVZ patches to the kernel:
<pre>
# gzip -d patch-026test012-combined.gz
# patch -p1 < patch-026test012-combined
</pre>
<!--T:37-->
# gzip -dc patch-ovz{{krel}}-combined.gz | patch -p1
 
=== Configure === <!--T:38-->
Now we need to place the config and build the kernel:
<pre>
# cp kernel-2.6.16-026test012-i686-smp.config.ovz .config
# make oldconfig
# make
</pre>
<!--T:39--># cp kernel-{{kver}}-i686-smp.config.ovz .config # make oldconfig <!--T:40-->On this stage, you can modify your kernel configuration to better suit your needs.  <!--T:41-->{{Note|Make sure all OpenVZ related options are set. See [[kernel configuration]].}} === Build === <!--T:42--> # make # make modules === Installation ===<!--T:43-->After successfull a successful build of the kernel it can be installed on the machine with the following commands run under '''root''' user:  <pre!--T:44-->
# make install
</pre> # make modules_install
<!--T:45-->
Also you need to edit your GRUB or LILO config to make your kernel available for boot.
</translate>
[[Category:HOWTO]][[Category:Kernel]][[Category: Installation]]

Navigation menu