I recently saw an example of topas running in a colleague’s putty session, and wondered whether a similar advanced utility existed for Linux. While top is good for the quick and dirty view into Linux goings on, there surely must be a utility that gives a more detailed view into Linux resource usage, like topas does for AIX. So I did some looking around and found atop. In order to get the full benefit of additional per-process statistics from atop, kernel patches are needed that provide the necessary counters. I thought this was a good opportunity to do two things then. Patch a Redhat Enterprise kernel to get full benefit of atop and then recompile the newly patched source into an installable kernel RPM. This will also yield a kernel-devel RPM that we will need in order to recompile VMWare guest modules, I need this because this devel environment is a RHEL5.2 VMWare server 2 guest.
Let’s get to it then.
Goals:
Environment:
VMWare Server 2
Redhat Enterprise Linux 5.2
Get kernel src.rpm file
ftp://ftp.redhat.com/pub/redhat/linux/enterprise/5Server/en/os/SRPMS/
Install
rpm -ivh kernel-2.6.18-92.el5.src.rpm
Extract
cd /usr/src/redhat/SPECS/
rpmbuild -bp --target=i686 kernel-2.6.spec
I’ll take the opportunity here to say that this RHEL5 guest is a development environment, so I don’t care about building the kernel RPM as root. But a more appropriate method can be seen here if you prefer.
Get and extract atop kernel patches for kernel version 2.6.18
Download the patch tar file from atop website: http://www.atcomputing.nl/Tools/atop/download-patch.html
For this, I grabbed atoppatch-kernel-2.6.18.tar.gz and extracted
cd ~
tar xvzf atoppatch-kernel-2.6.18.tar.gz
cd atoppatch-kernel-2.6.18/
Copy atop patch files into build environment sources directory
cp 01patch-2.6.18_atopcnt /usr/src/redhat/SOURCES/linux-2.6-atop_atopcnt.patch
cp 02patch-2.6.18_atopacct /usr/src/redhat/SOURCES/linux-2.6-atop_atopacct.patch
Edit the source RPM spec file to enable the application of these patches during kernel RPM build
cd /usr/src/redhat/SPECS
vim kernel-2.6.spec
Add references to the atop patch files and add the lines for the actual application of them during the build. Only relevant sections of the spec file are shown
We should also modify the release name to better distinguish that this is with atop changes. It will result in a kernel named 2.6.18-92.atop.el5
%define release 92.atop%{?dist}%{?buildid}
~
~
Patch22556: linux-2.6-scsi-cciss-allow-kexec-to-work.patch
Patch22557: linux-2.6-fs-race-condition-in-dnotify.patch
# locally added atop patches
Patch55555: linux-2.6-atop_atopcnt.patch
Patch55556: linux-2.6-atop_atopacct.patch
# adds rhel version info to version.h
Patch99990: linux-2.6-rhel-version-h.patch
# empty final patch file to facilitate testing of kernel patches
Patch99999: linux-kernel-test.patch
~
~
%patch22556 -p1
%patch22557 -p1
%patch55555 -p1
%patch55556 -p1
Build the base kernel
time rpmbuild -bb --target=i686 --with baseonly --without kabichk kernel-2.6.spec
Since we have modified the configuration to accomodate our patches, we need to use the –without kabichk flag to avoid
*** ERROR – ABI BREAKAGE WAS DETECTED ***
and the subsequent RPM build error
Install the new kernel and kernel development packages
rpm -ivh --force /usr/src/redhat/RPMS/i686/kernel-2.6.18-92.atop.el5.i686.rpm
rpm -ivh --force /usr/src/redhat/RPMS/i686/kernel-devel-2.6.18-92.atop.el5.i686.rpm
Edit /boot/grub/grub.conf to default to this new kernel, or select it at the grub boot menu at boot. Reboot and re-run vmware-config-tools to recompile guest OS modules against this new kernel, pointing the installer to the header files directory provided by the kernel-devel package: /usr/src/kernels/2.6.18-92.atop.el5-i686/include
Now install the atop package
rpm -ivh atop-1.23-1.i386.rpm
Now that we patched the kernel with atop changes, rebuilt it and booted from it, we have access to the additional atop features.
