Editing Kernel build
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This FAQ will help you in case you want to apply some patches to the kernel on your own or rebuild it from sources. | 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. | On RPM based distros such as RedHat Enterprise Linux/CentOS, Fedora Core or SUSE one can simpy rebuild kernel from SRPM. | ||
For other distros it is required to install sources, build and install kernel manually. The below are given the details for both cases. | 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 == | + | == Rebuilding kernel from SRPM == |
| − | === Find out $TOPDIR === | + | === Find out $TOPDIR === |
'''Note''': paths in some of the commands below include $TOPDIR, which is distribution-dependent and can be further redefined by user. To find out the proper location of $TOPDIR on your system, issue this command: | '''Note''': paths in some of the commands below include $TOPDIR, which is distribution-dependent and can be further redefined by user. To find out the proper location of $TOPDIR on your system, issue this command: | ||
| − | + | TOPDIR=$(rpm --eval "%{_topdir}"); echo $TOPDIR | |
| − | TOPDIR=$(rpm --eval "%{_topdir}"); echo $TOPDIR | ||
| − | === Download === | + | === Download === |
Source RPMS for different OpenVZ kernel branches can be downloaded from http://openvz.org/download/kernel/. You can also access http://download.openvz.org/kernel/ directly, or use one of the [[download mirrors|mirrors]]. | Source RPMS for different OpenVZ kernel branches can be downloaded from http://openvz.org/download/kernel/. You can also access http://download.openvz.org/kernel/ directly, or use one of the [[download mirrors|mirrors]]. | ||
| − | === Installation === | + | === Installation === |
Install the downloaded SRC RPM with the following command: | Install the downloaded SRC RPM with the following command: | ||
| − | + | # rpm -ihv ovzkernel-{{kver}}-{{krel}}.src.rpm | |
| − | # rpm -ihv ovzkernel-{{kver}}-{{krel}}.src.rpm | ||
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After successfull installation, you can usually find kernel sources in <code>$TOPDIR/SOURCES/</code> | After successfull installation, you can usually find kernel sources in <code>$TOPDIR/SOURCES/</code> | ||
and kernel spec file (<code>kernel-ovz.spec</code>) in <code>$TOPDIR/SPECS</code>. | and kernel spec file (<code>kernel-ovz.spec</code>) in <code>$TOPDIR/SPECS</code>. | ||
| − | === Adding your own patches === | + | === Adding your own patches === |
To modify the kernel one needs just to add specific patches to the kernel spec file and put this patch into <code>$TOPDIR/SOURCES</code> directory. | 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. | ||
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Put your patch into SOURCES directory with the following command: | Put your patch into SOURCES directory with the following command: | ||
| − | + | # cp <patch> $TOPDIR/SOURCES/ | |
| − | # cp <patch> $TOPDIR/SOURCES/ | ||
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Then open spec file <code>$TOPDIR/SPECS/kernel-ovz.spec</code> in the editor and add the following lines: | Then open spec file <code>$TOPDIR/SPECS/kernel-ovz.spec</code> in the editor and add the following lines: | ||
| − | + | Patch100000: <patch-name> | |
| − | Patch100000: <patch-name> | ||
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and | and | ||
| − | + | %patch100000 -p1 | |
| − | %patch100000 -p1 | ||
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in appropriate places where similar text lines are. | in appropriate places where similar text lines are. | ||
| − | === Adjust kernel version === | + | === Adjust kernel version === |
Before rebuilding the kernel make sure that you adjusted the kernel version in <code>kernel-ovz.spec</code>. | Before rebuilding the kernel make sure that you adjusted the kernel version in <code>kernel-ovz.spec</code>. | ||
This will help you to distinguish binaries then from already existing kernels | This will help you to distinguish binaries then from already existing kernels | ||
(or from the official OpenVZ kernels). To do so, edit the <code>$TOPDIR/SPECS/kernel-ovz.spec</code> file and replace the following line: | (or from the official OpenVZ kernels). To do so, edit the <code>$TOPDIR/SPECS/kernel-ovz.spec</code> file and replace the following line: | ||
| − | + | %define ksubrelease 1 | |
| − | %define ksubrelease 1 | ||
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with something like | with something like | ||
| − | + | %define ksubrelease 1my.kernel.v1 | |
| − | %define ksubrelease 1my.kernel.v1 | ||
| − | === Modifying configs === | + | === Modifying configs === |
If you want to modify the kernel config, you need to do the following before you continue with [[#Building RPMs|the next step]]. | If you want to modify the kernel config, you need to do the following before you continue with [[#Building RPMs|the next step]]. | ||
| − | + | # cd $TOPDIR/SPECS | |
| − | # cd $TOPDIR/SPECS | ||
# rpmbuild -bp kernel-ovz.spec | # rpmbuild -bp kernel-ovz.spec | ||
# cd $TOPDIR/BUILD/kernel-{{kver}}/linux-{{kver}} | # cd $TOPDIR/BUILD/kernel-{{kver}}/linux-{{kver}} | ||
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'''Note''': Make sure all OpenVZ related options are set. See [[kernel configuration]] | '''Note''': Make sure all OpenVZ related options are set. See [[kernel configuration]] | ||
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There you will find the configuration files in the subdirectory <code>config/*.config</code>. Copy the one you want to modifiy to <code>$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]]. | There you will find the configuration files in the subdirectory <code>config/*.config</code>. Copy the one you want to modifiy to <code>$TOPDIR/BUILD/kernel-{{kver}}/linux-{{kver}}/.config</code>. Then you can do a make menuconfig or something similar to adjust the kernel configuration. Note that some kernel configuration issues are described at [[kernel configuration]]. | ||
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Next, copy <code>$TOPDIR/BUILD/kernel-{{kver}}/linux-{{kver}}/.config</code> to the <code>$TOPDIR/SOURCES</code> directory, but use the corresponding file name in the target directory. | Next, copy <code>$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 === | + | Some background information on this procedure can be found in the following thread: http://www.arcknowledge.com/gmane.comp.audio.planetccrma.general/2004-11/msg00018.html |
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| + | === Building RPMs === | ||
To rebuild the kernel, type the following commands: | To rebuild the kernel, type the following commands: | ||
| − | + | # cd $TOPDIR/SPECS | |
| − | # cd $TOPDIR/SPECS | ||
# rpmbuild -ba --target=i686 kernel-ovz.spec | # rpmbuild -ba --target=i686 kernel-ovz.spec | ||
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After successfull kernel compilation binary RPMs can be found at <code>$TOPDIR/RPMS/i686</code>. | After successfull kernel compilation binary RPMs can be found at <code>$TOPDIR/RPMS/i686</code>. | ||
| − | == Rebuilding kernel from sources == | + | == Rebuilding kernel from sources == |
| − | === Download === | + | === Download === |
To compile OpenVZ linux kernel one need to download the original linux kernel sources and OpenVZ patches for it. | To compile OpenVZ linux kernel one need to download the original linux kernel sources and OpenVZ patches for it. | ||
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Linux kernel can be found at [http://www.kernel.org/ kernel.org], e.g. {{kver}} kernel can be downloaded [http://www.kernel.org/pub/linux/kernel/v2.6/linux-{{kver}}.tar.bz2 from here]. | Linux kernel can be found at [http://www.kernel.org/ kernel.org], e.g. {{kver}} kernel can be downloaded [http://www.kernel.org/pub/linux/kernel/v2.6/linux-{{kver}}.tar.bz2 from here]. | ||
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Appropriate OpenVZ patches for this kernel version can be found at <nowiki>http://openvz.org/download/kernel/branches/<branch>/<version>/patches/</nowiki>. For example, at the moment there is a patch [http://download.openvz.org/kernel/branches/{{kver}}/{{krel}}/patches/patch-ovz{{krel}}-combined.gz patch-ovz{{krel}}-combined.gz] available. | Appropriate OpenVZ patches for this kernel version can be found at <nowiki>http://openvz.org/download/kernel/branches/<branch>/<version>/patches/</nowiki>. For example, at the moment there is a patch [http://download.openvz.org/kernel/branches/{{kver}}/{{krel}}/patches/patch-ovz{{krel}}-combined.gz patch-ovz{{krel}}-combined.gz] available. | ||
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Kernel configs are also available at OpenVZ download site. Most frequently SMP config is used, so let's download [http://download.openvz.org/kernel/branches/{{kver}}/{{krel}}/configs/kernel-{{kver}}-i686-smp.config.ovz kernel-{{kver}}-i686-smp.config.ovz] | Kernel configs are also available at OpenVZ download site. Most frequently SMP config is used, so let's download [http://download.openvz.org/kernel/branches/{{kver}}/{{krel}}/configs/kernel-{{kver}}-i686-smp.config.ovz kernel-{{kver}}-i686-smp.config.ovz] | ||
for this example. | for this example. | ||
| − | === Prepare === | + | === Prepare === |
First, extract the kernel sources from archive: | First, extract the kernel sources from archive: | ||
| − | + | # tar vjxf linux-{{kver}}.tar.bz2 | |
| − | # tar vjxf linux-{{kver}}.tar.bz2 | ||
# cd linux-{{kver}} | # cd linux-{{kver}} | ||
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Apply OpenVZ patches to the kernel: | Apply OpenVZ patches to the kernel: | ||
| − | + | # gzip -dc patch-ovz{{krel}}-combined.gz | patch -p1 | |
| − | # gzip -dc patch-ovz{{krel}}-combined.gz | patch -p1 | ||
| − | === Configure === | + | === Configure === |
Now we need to place the config and build the kernel: | Now we need to place the config and build the kernel: | ||
| − | + | # cp kernel-{{kver}}-i686-smp.config.ovz .config | |
| − | # cp kernel-{{kver}}-i686-smp.config.ovz .config | ||
# make oldconfig | # make oldconfig | ||
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On this stage, you can modify your kernel configuration to better suit your needs. | On this stage, you can modify your kernel configuration to better suit your needs. | ||
| − | + | '''Note''': Make sure all OpenVZ related options are set. See [[kernel configuration]] | |
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| − | === Build === | + | === Build === |
# make | # make | ||
# make modules | # make modules | ||
| − | === Installation === | + | === Installation === |
After a successful build of the kernel it can be installed on the machine with the following commands run under '''root''' user: | After a successful build of the kernel it can be installed on the machine with the following commands run under '''root''' user: | ||
| − | + | # make install | |
| − | # make install | ||
# make modules_install | # make modules_install | ||
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Also you need to edit your GRUB or LILO config to make your kernel available for boot. | Also you need to edit your GRUB or LILO config to make your kernel available for boot. | ||
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| − | [[Category: HOWTO]] | + | [[Category:HOWTO]] |
| − | [[Category: Kernel | + | [[Category:Kernel]] |
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