[lttng-dev] lttng, lttng-sessiond and the tracing group

[Thibault, Daniel]

-----Message d'origine-----
De : christian.babeux at 0x80.ca [mailto:christian.babeux at 0x80.ca] De la part de Christian Babeux
Envoyé : 6 février 2013 12:52

> >    First observation
>
> I'm not able to reproduce your first observation on my machine.
>
> > [...]
> > $ sudo lttng -vvv create rootlevel
> > Session rootlevel created.
> > Traces will be written in 
> > /home/daniel/lttng-traces/rootlevel-20130206-091954
>
> This looks wrong. Traces should be written under the /root/lttng-traces. Are you sure this command has effectively been issued has the root user? It looks like it was issued as your normal user hence the "session=rootlevel" in your user ~/.lttngrc. Could you try su'ing to root instead?

   This may very well be an "Ubuntism".  All flavours of Ubuntu use a locked root and force all users to systematically use sudo; the su command won't go anywhere because there is no root password.  (It is possible, though strongly discouraged, to unlock and later relock the root account, as explained here: https://help.ubuntu.com/community/RootSudo)  The short and sweet of it is that (nearly) all super-user operations under Ubuntu will be conducted by a user (with sudo privileges), not by the root account.  Hence the shenanigans I ran into.  It sounds like LTTng will have to adjust the way it allocates the root .lttngrc path under Ubuntu systems, so that it uses /root/.lttngrc instead of ~/.lttngrc

Daniel U. Thibault
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