[lttng-dev] Having trouble with LTTng folders

[Mathieu Desnoyers]

----- Original Message -----

> From: "Michael Steppe" <msteppe91 at gmail.com>
> To: lttng-dev at lists.lttng.org
> Sent: Tuesday, November 19, 2013 8:38:53 AM
> Subject: [lttng-dev] Having trouble with LTTng folders

> Hello!

> I am currently running lttng-tools 2.0.4 on CentOS 6.3 (unfortunately I
> cannot upgrade either at this time).

> I have created a plugin in Eclipse (called LTTng Control) that allows users
> to trace without the command line. It is just a simple GUI with buttons that
> essentially relate to the system calls in the terminal. One of the options I
> have allows users to manually connect, via the IP address, to another VM to
> trace remotely on that VM. So far I support RHEL 6.1, 6.3, 6.4, and CentOS
> 6.3 remote VMs. I have made all the system calls as seen below, creating
> each trace in /tmp and calling all lttng calls on that specific trace:

> lttng create TRACE_<date>_<time> -o /tmp/TRACE_<date>_<time>
> lttng enable-event -a -k TRACE_<date>_<time>
> lttng start TRACE_<date>_<time>
> lttng stop TRACE_<date>_<time>
> lttng destroy TRACE_<date>_<time>

> I then change ownership of each trace folder (and all subfolders) after the
> destroy command so that the user who signed in when connecting to the remote
> VM now has ownership of the trace and can view and open the trace files in
> the LTTng Eclipse Viewer plugin.

> This ALL works PERFECTLY on a remote VM where I had the root account "adduser
> user". Unfortunately, I need to set up users a little differently for
> work...

> I have set up another VM that only has a root account. Using Active
> Directory, I set up user accounts from my work's development network (giving
> everyone here at work the ability to sign in with their usernames and
> passwords), meaning root does not have permissions to edit files owned by
> these users. Here lies my problem:

> Let's say I sign in to the remote VM as user = "Scott". When I try and
> attempt to perform the "create" command through my plugin, I get:

> An error was encountered on 10.176.15.180 (10.176.15.180)
> Host: 10.176.15.180
> Command: /usr/bin/lttng create TRACE_111913_082211 -o
> /tmp/TRACE_111913_082211
> Exit Code: 1
> No output stream captured
> Error Output:
> Error: Unable to create config file
> Error: Command error

> I am assuming it is unable to create the config file because the all the
> tracing folders and files are created and owned by root and root does not
> have access to write to Scott's home directory, where the config file should
> go. The trace is actually created, but not .lttngrc file is created. If I
> perform an 'lttng list" in the remote VM (signed in as Scott), I can see the
> TRACE_<date>_<time> and that its status is [inactive] (because we haven't
> started the trace yet).

> My question is this. Is there a way, in this version of LTT, to have the
> .lttng and .lttngrc folder/file to be located somewhere else? That way, all
> the tracing is done by root and the trace files are stored in /tmp and when
> the tracing is finished, root can give Scott ownership of the trace files?

> I know that was long and possibly confusing so let me know if you have any
> questions. Love your tracing tool by the way!

I don't think this old version (2.0.4) allowed that. You will probably need to play with your HOME env. var. 
to put the .lttngrc file elsewhere. We introduced LTTNG_HOME env. var. later, but I don't think it was 
present in 2.0.4. 

Thanks, 

Mathieu 

> Thanks!
> Michael Steppe

> _______________________________________________
> lttng-dev mailing list
> lttng-dev at lists.lttng.org
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-- 
Mathieu Desnoyers 
EfficiOS Inc. 
http://www.efficios.com 
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