The goal is to have an i686 kernel with 4GB+ memory support (PAE) with OpenVZ, IBCS, and DRBD.

Environment:
Dell 2900
-8 Cores (1.60Ghz)
-24GB RAM

Operating System:
CentOS 5

Lets start by making ourselves a working directory:

mkdir -p /usr/src/kernels/2.6.24_vz_drbd_ibcs/src
cd /usr/src/kernels/2.6.24_vz_drbd_ibcs/src

Then we need to collect all the parts to build the patched kernel/modules:

wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.24.tar.gz
wget http://oss.linbit.com/drbd/8.3/drbd-8.3.0.tar.gz
wget http://voxel.dl.sourceforge.net/sourceforge/linux-abi/ibcs-3_7.tgz
wget http://download.openvz.org/kernel/branches/2.6.24/2.6.24-ovz006.5/patches/patch-ovz006.5-combined.gz
wget http://download.openvz.org/kernel/branches/2.6.24/2.6.24-ovz006.5/configs/kernel-2.6.24-i686-PAE.config.ovz

Now that we have all the pieces we need lets start extractin & patchin. BTW, I’ll start all the command blocks with a pwd to show you where I am…:

pwd
/usr/src/kernels/2.6.24_vz_drbd_ibcs/src
tar xzf linux-2.6.24.tar.gz -C ..
tar xzf drbd-8.3.0.tar.gz -C ..
mkdir ../ibcs
tar xzf ibcs-3_7.tgz -C ../ibcs
cp patch-ovz006.5-combined.gz ..
cd ..

Ok stay calm, I just put all the source files in /src, and will build the kernel in 2.6.24_vz_drbd_ibcs.

pwd
/usr/src/kernels/2.6.24_vz_drbd_ibcs
gunzip -c patch-ovz006.5-combined.gz | patch -p0 patch-ovz006.5-combined.gz

Lets continue by patching in drbd. You have to actually patch this in as opposed to building it as a module since that doesn’t work.

pwd
/usr/src/kernels/2.6.24_vz_drbd_ibcs
cd drbd-8.3.0
make KDIR=/usr/src/kernels/2.6.24_vz_drbd_ibcs/linux-2.6.24 kernel-patch
cp patch-linux-2.6.24-drbd-8.3.0 ..
cd ..
patch -p0 < patch-linux-2.6.24-drbd-8.3.0

pwd
/usr/src/kernels/2.6.24_vz_drbd_ibcs
cd linux-2.6.24
cp ../src/kernel-2.6.24-i686-PAE.config.ovz ./.config
make menuconfig

After you’re dropped into menuconfig you need to set drbd to(to compile drbd into the kernel)

Device Drivers > Block devices >     DRBD Distributed Replicated Block Device support

At the moment you have a vanilla 2.6.24 kernel with OpenVZ ovz006.5 (patched) and DRBD 8.3.0 RC2 (patched). The only thing left is IBCS which we will install as a module after we have compiled and booted into the OS. As for now lets go ahead and compile, install, and boot.

time make -j7 rpm

The build command ‘time make -j7 rpm’ will tell you how long it took to build at the end, the -j is how many jobs it can run at once (8 cores – 1 core for OS = 7 cores) and ‘rpm’ will do package it up for you in and store it at /usr/src/redhat/RPMS{*}

If it compiles correctly you should get no errors, and see something like this:

--output from compile--

real	6m27.445s
user	37m59.198s
sys	6m18.564s

Then navigate to /usr/src/redhat/{athlon, i386, i486, i586, i686, noarch} depending on your archetecture. Mine was in i386.

ls
kernel-2.6.24-2.i386.rpm
pwd
/usr/src/redhat/RPMS/i386
rpm -i kernel-2.6.24-2.i386.rpm

You should get something like the above…

Then you need to make the ramdisk:

mkinitrd /boot/initrd-2.6.24.img 2.6.24

After that add an entry to grub to test your new kernel with OpenVZ and DRBD.

title CentOS (2.6.24 VZ_DRBD_IBCS)
        root(hd0,0)
        kernel /vmlinuz-2.6.24 ro root=LABEL=/
        initrd /initrd-2.6.24.img

If everything goes as expected, then you should boot up. If it doesn’t boot, or boots into the wrong kernel then you should check that you did everything correctly… Anywho, you should now be booted into your new kernel.

Lets continue by installing IBCS, and finishing up…

pwd
/usr/src/kernels/2.6.24_vz_drbd_ibcs/ibcs
time make

If you received no errors, then continue edit /etc/rc.local to startup icbs on startup. Add the following to the end of your /etc/rc.local:

/usr/src/kernels/2.6.24_vz_drbd_ibcs/ibcs/abi_ldr

You could move abi_ldr to /usr/bin if you would like, and just make sure to have the path above correspond where you decide to put abi_ldr.

You’re Finished!

Resources:
http://www.drbd.org/users-guide/s-build-from-source.html
http://wiki.openvz.org/Download/kernel/2.6.24/2.6.24-ovz006.5
http://www.howtoforge.com/kernel_compilation_centos