Re: [linuxtools-dev] TCF and remote profiling/tracing

[Corey Ashford <cjashfor@xxxxxxxxxxxxxxxxxx>]

On 05/25/2011 02:52 PM, Jeff Johnston wrote:
...
> 2. I would like to cease the shipping of the rpm over to the remote
> system.  Instead, I would like to create a new Fedora/RHEL package
> containing our TCF agent(s).  That way it can be installed from the
> remote side using the normal mechanisms.  This prevents the client from
> having to store rpms for all supported systems and platforms.  We can
> maintain the package for Fedora/RHEL.
> 
> User's on other systems can pressure their maintainers to add the
> package or they can start the agent manually and do the manual
> specification using the environment variables as they can today.
> 

How do you handle the case where the user is running an older distro?
Let's say I'm targeting RHEL 6.0, which doesn't have this RPM?  There
should be a convenient place where I can download the package source and
build an RPM manually, or even better, pre-built RPM's for older distros.

>...
> 4. The tcf agent requires port 1534 to be open.  The current set-up
> doesn't ensure this.  I think that it should take care of this.
> 

I think there should be an option to utilize an ssh tunnel for all of
the communication.  In fact, I think this ought to be the default.
Opening holes in firewalls is troublesome and has security risks.

> 5. The tcf agent runs as a root daemon.  This is dangerous since the tcf
> agent has capability of doing just about anything (starting processes,
> moving files around).  Does Lttng require root access?  Valgrind does
> not, but OProfile for instance, does.  I have recently worked on setting
> up policy kit to run /usr/bin/opcontrol (using pkexec and having a
> policy file).

The Linux "perf" tool requires root privilege if you perform a
system-wide measurement (per-cpu profiling or event counting).  So,
unlike OProfile, you only sometimes need root access.

On another subject, from our perspective, it would be nice if there were
some standardized way to extend the functionality of the target agent,
perhaps through .so plug-ins, so that custom tools can make use of the
agent.

- Corey