How to convert (and fixup) the RedHat RPM to run on Debian/Ubuntu

In an earlier post I had shown how I got the Xplat agent running on Ubuntu. I perfected the technique over time, and what follows is a step-by-step process on how to convert and change the RedHat package to run on Debian/Ubuntu. Of course this is still a hack… but some people asked me to detail it a bit more. At the same time, the cross platform team is working to update the the source code on codeplex with extra bits that will make more straightforward to grab it, modify it and re-compile it than it is today. Until then, here is how I got it to work.

I assume you have already copied the right .RPM package off the OpsMgr server’s /AgentManagement directory to the Linux box here. The examples below refer to the 32bit package, but of course the same identical technique would work for the 64bit version.

We start by converting the RPM package to DEB format:

root# alien -k scx-1.0.4-258.rhel.5.x86.rpm –scripts

scx_1.0.4-258_i386.deb generated

 

Then we need to create a folder where we will extract the content of the package, modify stuff, and repackage it:

root# mkdir scx_1.0.4-258_i386

root# cd scx_1.0.4-258_i386

root# ar -x ../scx_1.0.4-258_i386.deb

root# mkdir debian

root# cd debian

root# mkdir DEBIAN

root# cd DEBIAN

root# cd ../..

root# rm debian-binary

root# mv control.tar.gz debian/DEBIAN/

root# mv data.tar.gz debian/

root# cd debian

root# tar -xvzf data.tar.gz

root# rm data.tar.gz

root# cd DEBIAN/

root# tar -xvzf control.tar.gz

root# rm control.tar.gz

Now we have the “skeleton” of the package easily laid out on the filesystem and we are ready to modify the package and add/change stuff to and in it.

 

First, we need to add some stuff to it, which is expected to be found on a redhat distro, but is not present in debian. In particular:

1. You should copy the file “functions” (that you can get from a redhat/centos box under /etc/init.d) under the debian/etc/init.d folder in our package folder. This file is required/included by our startup scripts, so it needs to be deployed too.

Then we need to chang some of the packacge behavior by editing files under debian/DEBIAN:

2. edit the “control” file (a file describing what the package is, and does):

clip_image002

3. edit the “preinst” file (pre-installation instructions): we need to add instructions to copy the “issue” file onto “redhat-release” (as the SCX_OperatingSystem class will look into that file, and this is hard-coded in the binary, we need to let it find it):

clip_image004

these are the actual command lines to add for both packages (DEBIAN or UBUNTU):

# symbolic links for libaries called differently on Ubuntu and Debian vs. RedHat

ln -s /usr/lib/libcrypto.so.0.9.8 /usr/lib/libcrypto.so.6

ln -s /usr/lib/libssl.so.0.9.8 /usr/lib/libssl.so.6

the following bit would be Ubuntu-specific:

#we need this file for the OS provider relies on it, so we convert what we have in /etc/issue

#this is ok for Ubuntu (“Ubuntu 9.0.4 \n \l” becomes “Ubuntu 9.0.4”)

cat /etc/issue | awk '/\\n/ {print $1, $2}' > /etc/redhat-release

while the following bit is Debian-specific:

#this is ok for Debian (“Debian GNU/Linux 5.0 \n \l” becomes “Debian GNU/Linux 5.0”)

cat /etc/issue | awk '/\\n/ {print $1, $2, $3}' > /etc/redhat-release

 

4. Then we edit/modify the “postinst” file (post-installation instructions) as follows:

a. remove the 2nd and 3rd lines which look like the following

RPM_INSTALL_PREFIX=

export RPM_INSTALL_PREFIX

as they are only useful for the RPM system, not DEB/APT, so we don’t need them.

b. change the following 2 functions which contain RedHat-specific commands:

configure_pegasus_service() {

           /usr/lib/lsb/install_initd /etc/init.d/scx-cimd

}

start_pegasus_service() {

           service scx-cimd start

}

c. We need to change in the Debian equivalents for registering a service in INIT and starting it:

configure_pegasus_service() {

               update-rc.d scx-cimd defaults

}

start_pegasus_service() {

              /etc/init.d/scx-cimd start

}

5. Modify the “prerm” file (pre-removal instructions):

a. Just like “postinst”, remove the lines

RPM_INSTALL_PREFIX=

export RPM_INSTALL_PREFIX

b. Locate the two functions stopping and un-installing the service

stop_pegasus_service() {

         service scx-cimd stop

}

unregister_pegasus_service() {

          /usr/lib/lsb/remove_initd /etc/init.d/scx-cimd

}

c. Change those two functions with the Debian-equivalent command lines

stop_pegasus_service() {

           /etc/init.d/scx-cimd stop

}

unregister_pegasus_service() {

           update-rc.d -f scx-cimd remove

}

At this point the change we needed have been put in place, and we can re-build the DEB package.

Move yourself in the main folder of the application (the scx_1.0.4-258_i386 folder):

root# cd ../..

Create the package starting from the folders

root# dpkg-deb –build debian

dpkg-deb: building package `scx' in `debian.deb'.

Rename the package (for Ubuntu)

root# mv debian.deb scx_1.0.4-258_Ubuntu_9_i386.deb

Rename the package (for Debian)

root# mv debian.deb scx_1.0.4-258_Debian_5_i386.deb

Install it

root# dpkg -i scx_1.0.4-258_Platform_Version_i386.deb

All done! It should install and work!

 

Next step would be creating a Management Pack to monitor Debian and Ubuntu. It is pretty similar to what Robert Hearn has described step by step for CentOS, but with some different replacements of strings, as you can imagine. I have done this but have not written down the procedure yet, so I will post another article on how to do this as soon as I manage to get it standardized and reliable. There is a bit more work involved for Ubuntu/Debian… as some of the daemons/services have different names, and certain files too… but nothing terribly difficult to change so you might want to try it already and have a go at it!

In the meantime, as a teaser, here’s my server’s (http://www.muscetta.com) performance, being monitored with this “hack”:

image

 

Disclaimer

The information in this weblog is provided "AS IS" with no warranties, and confers no rights. This weblog does not represent the thoughts, intentions, plans or strategies of my employer. It is solely my own personal opinion. All code samples are provided "AS IS" without warranty of any kind, either express or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose.
THIS WORK IS NOT ENDORSED AND NOT EVEN CHECKED, AUTHORIZED, SCRUTINIZED NOR APPROVED BY MY EMPLOYER, AND IT ONLY REPRESENT SOMETHING WHICH I'VE DONE IN MY FREE TIME. NO GUARANTEE WHATSOEVER IS GIVEN ON THIS. THE AUTHOR SHALL NOT BE MADE RESPONSIBLE FOR ANY DAMAGE YOU MIGHT INCUR WHEN USING THIS INFORMATION. The solution presented here IS NOT SUPPORTED by Microsoft.

SCX Evolutions

During the beta of the Cross-Platform extensions and of System Center Operations Manager 2007 R2, the product team had promised to eventually release the SCX Providers'source code.

Now that this promise has been mantained, and the SCX providers have been released on Codeplex at http://xplatproviders.codeplex.com/ it should be finally possible to entirely build your own unsupported agent package, starting from source code, without having to modify the original package as I have shown earlier on this blog.
Of course this will still be unsupported by Microsoft Product support, but will eventually work just fine!
This is an extraordinary event in my opinion, as it is not a common event that Microsoft releases code as open source, especially when this is part of one of the product it sells. I suspect we will see more of this as we going forward.

Also, at R2 release time, some official documentation about buildilng Cross-Plaform Management Packs has been published on Technet.

Anyway, I have in the past posted a number of posts on my blog under this tag http://www.muscetta.com/tag/xplat/ (I will continue to use that tag going forward) which show/describe how I hacked/modified both the existing MPs AND the SCX agent package to let it run on unsupported distributions (and I think they are still useful as they show a number of techniques about how to test, understand and troubleshoot the Xplat agent a bit. In fact, I have first learned how to understand and modify the RedHat MPs to monitor CentOS and eventually even modified the RPM package to run on Ubuntu (which also works on Debian 5/Lenny), eventually, as you can see because I am now using it to monitor – from home, across the Internet – the machine running this blog:

www.muscetta.com Performance in OpsMgr

Or even, with or without OpsMgr 2007 R2, you could write your own scripts to interact with those providers, by using your favourite Scripting Language.

After all, those experimentations with Xplat got me a fame of being a "Unix expert at Microsoft" (this expression still makes me laugh), as I was tweeting here:
Unix expert at Microsoft

But really, I have never hidden my interest for interoperability and the fact that I have been using Linux quite a bit in the past, and still do.

Also, one more related information is that the fine people at Xandros have released their Bridgeways Management Packs and at the same time also started their own blog at http://blog.xplatxperts.com/ where they discuss some troubleshooting techniques for the Xplat agent, both similar to what I have been writing about here and also – of course – specific to their own providers, that are in their XSM namespace.

Disclaimer

The information in this weblog is provided "AS IS" with no warranties, and confers no rights. This weblog does not represent the thoughts, intentions, plans or strategies of my employer. It is solely my own personal opinion. All code samples are provided "AS IS" without warranty of any kind, either express or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose.
THIS WORK IS NOT ENDORSED AND NOT EVEN CHECKED, AUTHORIZED, SCRUTINIZED NOR APPROVED BY MY EMPLOYER, AND IT ONLY REPRESENT SOMETHING WHICH I'VE DONE IN MY FREE TIME. NO GUARANTEE WHATSOEVER IS GIVEN ON THIS. THE AUTHOR SHALL NOT BE MADE RESPONSIBLE FOR ANY DAMAGE YOU MIGHT INCUR WHEN USING THIS INFORMATION. The solution presented here IS NOT SUPPORTED by Microsoft.

Installing the OpsMgr 2007 R2 SCX Agent on Ubuntu

You know since the beta1 of Xplat I have been busy with modifying the Redhat management pack and monitor CentOS with OpsMgr. Now, CentOS is a distribution that is pretty similar to RedHat, so the RPM package just runs, and it is only a matter of hacking a modified MP.

I never went really further in my experiments, mostly due to lack of time… but then yesterday I got a comment to this older post asking about Ubuntu. Of course I know about Ubuntu, and have been using Debian-based distributions for years. I actually even prefer them over RPM-based distributions such as RedHat or SuSE (personal preference). Heck, even this weblog is running on Debian!

Anyway, I never really tried to see if one of the existing RPM packages for RedHat or SuSE could be modified to run on Ubuntu. I will eventually test this on Debian too, but for now I used Ubuntu which tends to have slightly newer packages and libraries, overall. The machine I tested on is a Ubuntu Server 8.04.2. Older/newer versions might slightly differ.

BEWARE THAT ALL THAT FOLLOWS BELOW IS NOT SUPPORTED BY MICROSOFT. It is only described here for EXPERIMENTAL (==fun) purpose. DO NOT USE THIS IN A PRODUCTION ENVIRONMENT.

So, you are warned. Now let’s hack it.

The first thing to do is to copy the Redhat agent’s RPM package off your OpsMgr2007 R2 server in the “usual” path “C:Program FilesSystem Center Operations manager 2007AgentManagementUnixAgents”. Let’s grab the RHEL5 agent, which is called scx-1.0.4-248.rhel.5.x86.rpm in R2 RTM.

First we need to CONVERT the RPM package to the DEB package format used by Ubuntu, by using the ALIEN package:

sudo apt-get update
sudo apt-get install alien
sudo bash
alien -k scx-1.0.4-248.rhel.5.x86.rpm –scripts
dpkg -i scx_1.0.4-248_i386.deb

image

The converted package will install… but the script execution will fail in a few places – most notably in the generation of the certificate, as it is not able to locate the right openssl libraries, as shown in the screenshot above.

If the libssl.so.6 file cannot be found, you might be missing the “libssl-dev” package, which you can install as follows:

apt-get install libssl-dev

But even if it is installed, you will find that the files are still missing. This is not really true: actually, the files are there, but on Ubuntu they have a different name than on RedHat, that’s all. You can therefore create hardlinks to the “right” files, so that they are aliased and get found afterwards:

cd /usr/lib
ln -s libcrypto.so.0.9.8 libcrypto.so.6
ln -s libssl.so.0.9.8 libssl.so.6

So now when installing the package, the certificate generation will work:

image

You are nearly ready to go. You have to start the service by using the init scripts – the “service” command is RedHat-specific, that will still fail.

/etc/init.d/scx-cimd start is the “standard” way of starting daemons from init on Unix.

But it still fails, as it seems that the init script provided in the RedHat package is really searching for a file called “functions” which is present on RedHat and on CentOS, which provides re-usable functions for startup scripts to include:

image

How do you fix this? I just copied the /etc/init.d/functions file from a CentOS box to my Ubuntu box.

I copied it via SCP from the CentOS box I have:

cd /etc/init.d

scp root@centos.huis.dom:/etc/init.d/functions .

You can probably also find and fetch the file from the Internet (both CentOS and RedHat should have accessible repositories with all the files in their distributions, since it is open sourced).

After you have the file in place, the init script will be able to include it, will find the functions it needs, and the daemon/service will now start (even if with minor errors I have not investigated for now, but that don’t seem to be causing troubles):

image

and here you can see it is finally running:

image

So let’s try to issue a few queries as shown in a previous posts:

image

IT WORKS!!!

But… there is a “but”: not all classes actually return instances and values just yet. Most notably the “SCX_OperatingSystem” class does not seem to return anything right awy. That is a very important class, because is the one we would use to first discover the Operating System object in the Management Packs. So we need to fix it. The reason why the class does not return anything, is that the SCX provider is looking into the /etc/redhat-release file to return what OS version/distribution the machine is running. And the file is obviously not there on Ubuntu.

On all Linuxes there is a similar file, called /etc/issue… which again, we can copy with the other name and trick the provider into working:

cd /etc

cp issue redhat-release

And NOW, the SCX_OperatingSystem Class also returns an instance:

image

The next step would be “cooking” an MP to discover Ubuntu. More on this on a later post (maybe). I did not test all classes and their implementation… you can try to poke at them by following the instructions and commands on my previous post here. But this should get you started.

Disclaimer

The information in this weblog is provided "AS IS" with no warranties, and confers no rights. This weblog does not represent the thoughts, intentions, plans or strategies of my employer. It is solely my own personal opinion. All code samples are provided "AS IS" without warranty of any kind, either express or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose.
THIS WORK IS NOT ENDORSED AND NOT EVEN CHECKED, AUTHORIZED, SCRUTINIZED NOR APPROVED BY MY EMPLOYER, AND IT ONLY REPRESENT SOMETHING WHICH I'VE DONE IN MY FREE TIME. NO GUARANTEE WHATSOEVER IS GIVEN ON THIS. THE AUTHOR SHALL NOT BE MADE RESPONSIBLE FOR ANY DAMAGE YOU MIGHT INCUR WHEN USING THIS INFORMATION. The solution presented here IS NOT SUPPORTED by Microsoft.

Everybody loves T-Shirts, Etch.

An old photo of Joshua in his Debian T-Shirt has been used (with permission) by Holger Levsen in his presentation of http://www.debian-community.org/ given at FOSDEM 2007.
You can check out the slides here: http://layer-acht.org/slides/20070225-debian-community.org-prelaunch.pdf
and download a video here: http://meetings-archive.debian.net/pub/debian-meetings/2007/fosdem/

And yes, I feel very "debiany" today. In fact I just finished upgrading my server from Sarge to Etch and it went very smoothly, even if I had to reconfigure / migrate some settings – for example moving all the virtual server configuration from Apache 1.3 to 2.x … but it was about time for me to move my ass off 1.3! Among other things I am quite glad now I can use mod_mono and have it update with apt-get, instead than having my own compiled version with all sort of broken dependencies… also, it performs better – faster, and takes up the same amount of resources, which I would not have believed and I was in fact slightly concerned about. Nothing to be worried about, it turns out.

Some other guy was pointing me out today all the other improvements in the desktop-feature-space. I would not know, I am a runlevel-2 guy when it comes to linux.