Re: [RFC] Framework for easy distribution of SystemTap scripts.

[Prerna Saxena <prerna at linux dot vnet dot ibm dot com>]

On 02/03/2010 01:57 AM, Frank Ch. Eigler wrote:
> anithra wrote:
>
> > > Options:
> > > * --install -i Install the tapset rpm.
> > > * --run -r Runs the scripts
> > > for n minutes where n can be passed as a parameter. o The default value
> > > is 10 minutes. Post processing is performed after the script completes.
> > > * --start -s Invokes the script as a background process.
> > > * --stop -x Stops the script and performs post processing.
> > > * --uninstall -u Stops the script if running and uninstalls the rpm.
> > > * --all Installs the rpm, runs the scrip, processes the output and
> > > uninstalls the rpm.
> > > * --help Displays this usage text.
>
> It seems odd to have the file created by the framework-script to both
> manage installation as well as execution of the compiled systemtap
> materials.  Why install if it can be run directly?  If installed, how
> else to execute the systemtap module except via this file?
>
> Perhaps the stap-buildrpm widget should create a plain rpm that is
> self-explanatory to install, within which a /usr/bin/FOO shell script
> manage the execution of the script.
>
> It may be nice if stap-buildrpm interfaced with stap-initscripts, so
> that rpms produced this way were easily activatable from that scheme.
>
>
> - FChE

A little background on this framework might be of help in understanding 
the design goals for it. The idea was to build small diagnostic 
utilities based on systemtap that could be deployed on external systems 
(which may or may not have systemtap and dependencies like debuginfo 
installed). These could be used to glean specific information about the 
system.

Systemtap-generated kernel modules, along with systemtap runtime looked 
like a good mechanism to distribute such utilities.

We decided to package the precompiled kernel modules along with 
systemtap runtime binaries in an rpm. Also, we thought that the rpm 
installation ; systemtap module insertion, and data filtering and 
logging ought to be transparent to the support admin who is running this 
-- so we packaged the rpm alongwith a wrapper shell script that 
automates all these steps for the user. This was bundled in a 
self-extracting archive for simplicity of use.

This framework can be employed to build such diagnostic utilities on the 
fly.

The 'install' option in the shell script merely installs the rpm, ie, it 
copies the systemtap kernel module and runtime in a specified location. 
The 'uninstall' option removes systemtap kernel module and other files 
installed by the rpm. The 'run' option launches staprun to insert the 
systemtap generated kernel module, employs an optional post-processing 
script to filter the data logged, stores logs in a pre-specifed log 
file, and causes the systemtap kernel module to be clean-removed. The 
'all' option does all these steps in order.

Interfacing with initscripts is a good add-on, but the primary purpose 
was to deploy such diagnostics on installations that lack systemtap and 
dependencies -- it was meant to be self-sufficient.

The framework can be enhanced if it is found useful to begin with :-)

Regards,
--
Prerna Saxena
 as possible
Linux Technology Centre,
IBM Systems and Technology Lab,
Bangalore, India