table of contents
LTTNG-RELAYD(8) | LTTng Manual | LTTNG-RELAYD(8) |
NAME¶
lttng-relayd - LTTng 2 relay daemonSYNOPSIS¶
lttng-relayd [--background | --daemonize] [--control-port=URL] [--data-port=URL] [--live-port=URL] [--output=PATH] [-v | -vv | -vvv]
DESCRIPTION¶
The Linux Trace Toolkit: next generation <http://lttng.org/> is an open source software package used for correlated tracing of the Linux kernel, user applications, and user libraries.LTTng consists of Linux kernel modules (for Linux kernel tracing) and dynamically loaded libraries (for user application and library tracing).
The LTTng relay daemon is responsible for receiving trace data from possibly remote LTTng session/consumer daemons and for writing it to the local file system. The relay daemon also accepts LTTng live connections from compatible viewers; this is the official approach to viewing LTTng events as they are emitted.
The relay daemon listens by default on all network interfaces to gather trace data, but only on localhost for LTTng live connections.
The relay daemon does not require any particular permissions, as long as it can write to the output directory and listen on the configured ports. If a user is within a secured network and/or has proper firewall settings, lttng-relayd can listen to LTTng live connections from all network interfaces by specifying --live-port=tcp://localhost:5344.
Once a trace has been streamed completely, the trace can be processed by any tool that can process an LTTng trace located on the local file system.
Output directory¶
By default, the relay daemon writes the traces to:$LTTNG_HOME/lttng-traces/HOSTNAME/SESSION/DOMAIN
with:
HOSTNAME
SESSION
DOMAIN
You can override the default output directory prefix ($LTTNG_HOME/lttng-traces) with the --output option. The other parts depend on the remote configuration.
URL format¶
The --control-port, --data-port, and --live-port options specify URLs.The format of those URLs is:
tcp://(HOST | IPADDR):PORT
with:
(HOST | IPADDR)
PORT
OPTIONS¶
Daemon¶
-b, --background-d, --daemonize
-g GROUP, --group=GROUP
-o PATH, --output=PATH
See the Output directory section above for more information.
-v, --verbose
Three levels of verbosity are available, which are triggered by appending additional v letters to the option (that is, -vv and -vvv).
Ports¶
See the URL format section above for more information about the syntax of the following options' URL argument.-C URL, --control-port=URL
-D URL, --data-port=URL
-L URL, --live-port=URL
Program information¶
-h, --help-V, --version
ENVIRONMENT VARIABLES¶
LTTNG_ABORT_ON_ERRORLTTNG_NETWORK_SOCKET_TIMEOUT
LTTNG_RELAYD_HEALTH
FILES¶
$LTTNG_HOME/.lttng$LTTNG_HOME/lttng-traces
Note
$LTTNG_HOME defaults to $HOME when not explicitly set.
EXIT STATUS¶
01
3
LIMITATIONS¶
As of this version, only the TCP protocol is supported for both control and data ports. In future versions, TCP will remain the sole available protocol for control data since those communications are low-volume and need absolute reliability; trace data could be carried over UDP.For an unprivileged user running lttng-relayd, the maximum number of file descriptors per process is usually 1024. This limits the number of connections and opened trace files. This limit can be configured with ulimit(3).
BUGS¶
If you encounter any issue or usability problem, please report it on the LTTng bug tracker <https://bugs.lttng.org/projects/lttng-tools>.RESOURCES¶
COPYRIGHTS¶
This program is part of the LTTng-tools project.LTTng-tools is distributed under the GNU General Public License version 2 <http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html>. See the LICENSE <https://github.com/lttng/lttng-tools/blob/master/LICENSE> file for details.
THANKS¶
Special thanks to Michel Dagenais and the DORSAL laboratory <http://www.dorsal.polymtl.ca/> at École Polytechnique de Montréal for the LTTng journey.Also thanks to the Ericsson teams working on tracing which helped us greatly with detailed bug reports and unusual test cases.
AUTHORS¶
LTTng-tools was originally written by Mathieu Desnoyers, Julien Desfossez, and David Goulet. More people have since contributed to it.LTTng-tools is currently maintained by Jérémie Galarneau <mailto:jeremie.galarneau@efficios.com>.
SEE ALSO¶
lttng(1), lttng-sessiond(8), lttng-crash(1), lttng-ust(3), babeltrace(1)01/09/2017 | LTTng 2.9.3 |