Question about lttng daemons
Hi,
I can answer your first question ;)
Quoted 4 lines · changz
Hi all,
Is that possible to launch lttng daemons as a system service? i.e. we can start/stop/restart it like the services under
/etc/init.d.
Absolutely. Note that you only need to auto-start the lttng-sessiond. The consumerd daemons get started automatically by the sessiond when trace sessions are created. This is a nice way to start a root session daemon at boot time, which then allows users in the "tracing" group to use the kernel tracer without being root themselves.
We don't ship an example in the source tree, since this is usually distro-specific, but for reference you can look at the Upstart script that is available in the Ubuntu package:
http://bazaar.launchpad.net/~ubuntu-branches/ubuntu/quantal/lttng-tools/quantal/view/head:/debian/lttng-tools.lttng-sessiond.upstart
Alex
Quoted 13 lines
Another concern is if here is a way to recover or continue the dataflow once the daemons get crashed.
I hope some vital trace info can be still kept even if daemon crashes.BR
zheng_______________________________________________
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Hi guys,
Alexandre Montplaisir:
Quoted 19 lines
Hi,
I can answer your first question ;)
Quoted 5 lines · changz
Hi all,
Is that possible to launch lttng daemons as a system service? i.e. we can start/stop/restart it like the services under
/etc/init.d.Absolutely. Note that you only need to auto-start the lttng-sessiond. The consumerd daemons get started automatically by the sessiond when trace sessions are created. This is a nice way to start a root session daemon at boot time, which then allows users in the "tracing" group to use the kernel tracer without being root themselves.
Quoted 6 lines
We don't ship an example in the source tree, since this is usually distro-specific, but for reference you can look at the Upstart script that is available in the Ubuntu package:
http://bazaar.launchpad.net/~ubuntu-branches/ubuntu/quantal/lttng-tools/quantal/view/head:/debian/lttng-tools.lttng-sessiond.upstart
We could maybe provide this upstart script in extras/ ?
Quoted 6 lines
Alex
Quoted 3 lines
Another concern is if here is a way to recover or continue the dataflow once the daemons get crashed. I hope some vital trace info can be still kept even if daemon crashes.
Right now we *don't* have this kind of feature. We are hoping someday that we'll be able to dump the state or configuration of tracing session onto disk that can be later on loaded by another daemon for instance.
However, we do offer (upstream master not yet released) a health check API call which return the health status of the session daemon (lttng-sessiond). So for now, you can at least monitor the daemon but still no mechanism to save tracing session info.
Please note that if the daemon crashes, the tracers are NOT impacted meaning that user space applications don't crash, they will simply continue their way without tracing and the kernel tracing will also stop.
Cheers!
David
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BR zheng
Quoted 8 lines
Quoted 3 lines
_______________________________________________ lttng-dev mailing list [email protected]
http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev_______________________________________________ lttng-dev mailing list [email protected]
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We don't ship an example in the source tree, since this is usually distro-specific, but for reference you can look at the Upstart script that is available in the Ubuntu package:
Quoted 3 lines
We could maybe provide this upstart script in extras/ ?
Yes, probably, with also the systemd script and the old style initscript. (I've made both)
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Yannick Brosseau:
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We don't ship an example in the source tree, since this is usually distro-specific, but for reference you can look at the Upstart script that is available in the Ubuntu package:
Quoted 8 lines
Quoted 1 line
We could maybe provide this upstart script in extras/ ?
Yes, probably, with also the systemd script and the old style initscript. (I've made both)
Great! Send me that as a patch or pull request, I'll be glad to merge that!
David
Quoted 5 lines
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