[lttng-tools.git] / doc / man / lttng-sessiond.8

.TH "LTTNG-SESSIOND" "8" "January 31, 2012" "" ""

.SH "NAME"
lttng-sessiond \(em LTTng 2.x central tracing registry session daemon.

.SH "SYNOPSIS"

.PP
.nf
lttng-sessiond [OPTIONS]
.fi
.SH "DESCRIPTION"

.PP
The LTTng project aims at providing highly efficient tracing tools for Linux.
It's tracers help tracking down performance issues and debugging problems
involving multiple concurrent processes and threads. Tracing across multiple
systems is also possible.

The session daemon, acting as a tracing registry, allow you to interact with
multiple tracers (kernel and user-space) inside the same container, a tracing
session. Trace can be gathered from the kernel and/or instrumented applications
(lttng-ust(3)). Aggregating those traces is done using a viewer, like the
babeltrace(1) text viewer.

In order to trace the kernel, the session daemon needs to be running as root.
LTTng provides the use of a \fBtracing group\fP (default: tracing). Whomever is
in that group can interact with the root session daemon and thus trace the
kernel. Session daemons can co-exist meaning that you can have a session daemon
running as Alice that can be used to trace her applications along side with a
root daemon or even a Bob daemon. We highly recommend to start the session
daemon at boot time for stable and long term tracing.

The session daemon is in charge of managing trace data consumers by spawning
them when the time has come. The user don't need to manage the lttng-consumerd.
.SH "OPTIONS"

.PP
This program follow the usual GNU command line syntax with long options starting with
two dashes. Below is a summary of the available options.
.PP

.TP
.BR "-h, --help"
Show summary of possible options and commands
.TP
.BR "-v, --verbose"
Increase verbosity

There is three debugging level which will print on stderr. Maximum verbosity is
\fB-vvv\fP.
.TP
.BR "    --verbose-consumer"
Verbose mode for consumer. Activate DBG() macro.
.TP
.BR "-d, --daemonize"
Start as a daemon
.TP
.BR "-b, --background"
Start as a daemon, keeping console open
.TP
.BR "-g, --group=NAME"
Specify the tracing group name. (default: tracing)
.TP
.BR "-V, --version"
Show version number
.TP
.BR "-S, --sig-parent"
Send SIGUSR1 to parent pid to notify readiness.

This is used by \fBlttng(1)\fP to get notified when the session daemon is ready
to accept command. When building a third party tool over liblttng-ctl, this option
can be very handy to synchronize the control tool and the session daemon.
.TP
.BR "-q, --quiet"
No output at all.
.TP
.BR "    --no-kernel"
No kernel tracer support
.TP
.BR "-c, --client-sock=PATH"
Specify path for the client unix socket
.TP
.BR "-a, --apps-sock PATH"
Specify path for apps unix socket
.TP
.BR "    --kconsumerd-err-sock=PATH"
Specify path for the kernel consumer error socket
.TP
.BR "    --kconsumerd-cmd-sock=PATH
Specify path for the kernel consumer command socket
.TP
.BR "    --ustconsumerd32-err-sock=PATH
Specify path for the 32-bit UST consumer error socket
.TP
.BR "    --ustconsumerd64-err-sock=PATH
Specify path for the 64-bit UST consumer error socket
.TP
.BR "    --ustconsumerd32-cmd-sock=PATH
Specify path for the 32-bit UST consumer command socket
.TP
.BR "    --ustconsumerd64-cmd-sock=PATH
Specify path for the 64-bit UST consumer command socket
.TP
.BR "    --consumerd32-path=PATH
Specify path for the 32-bit UST consumer daemon binary
.TP
.BR "    --consumerd32-libdir=PATH
Specify path for the 32-bit UST consumer daemon libraries
.TP
.BR "    --consumerd64-path=PATH
Specify path for the 64-bit UST consumer daemon binary
.TP
.BR "    --consumerd64-libdir=PATH
Specify path for the 64-bit UST consumer daemon libraries
.SH "ENVIRONMENT VARIABLES"

.PP
Note that all command line options will override environment variables.
.PP

.PP
.IP "LTTNG_CONSUMERD32_BIN"
Specify the 32-bit consumer binary path. \fB--consumerd32-path\fP
override this variable.
.IP "LTTNG_CONSUMERD64_BIN"
Specify the 64-bit consumer binary path. \fB--consumerd64-path\fP
override this variable.
.IP "LTTNG_CONSUMERD32_LIBDIR"
Specifiy the 64-bit library path containing libconsumer.so.
\fB--consumerd32-libdir\fP override this variable.
.IP "LTTNG_CONSUMERD64_LIBDIR"
Specifiy the 32-bit library path containing libconsumer.so.
\fB--consumerd64-libdir\fP override this variable.
.IP "LTTNG_DEBUG_NOCLONE"
Debug-mode disabling use of clone/fork. Insecure, but required to allow
debuggers to work with sessiond on some operating systems.
.IP "LTTNG_APP_SOCKET_TIMEOUT"
Control the timeout of application's socket when sending and receiving
commands. Takes an integer parameter: the timeout value, in seconds.
After this period of time, the application is unregistered by the
session daemon. A value of 0 or -1 means an infinite timeout. Default
value is 5 seconds.
.IP "LTTNG_NETWORK_SOCKET_TIMEOUT"
Control timeout of socket connection, receive and send. Takes an integer
parameter: the timeout value, in milliseconds. A value of 0 or -1 uses
the timeout of the operating system (this is the default).
.SH "SEE ALSO"

.PP
babeltrace(1), lttng-ust(3), lttng(1)
.PP

.SH "LIMITATIONS"

.PP
For unprivileged user running lttng-sessiond, the maximum number of file
descriptors per process is usually 1024. This limits the number of traceable
applications since for each instrumented application there is two file
descriptors per-CPU and one more socktet for bidirectional communication.

For the root user, the limit is bumped to 65535. Future version will deal with
this limitation.
.PP

.SH "BUGS"

.PP
No show stopper bugs are known yet in this version.

If you encounter any issues or usability problem, please report it on our
mailing list <lttng-dev@lists.lttng.org> to help improve this project.
.SH "CREDITS"

.PP
lttng-sessiond is distributed under the GNU General Public License version 2. See the
file COPYING for details.
.PP
A Web site is available at http://lttng.org for more information on the LTTng
project.
.PP
You can also find our git tree at http://git.lttng.org.
.PP
Mailing lists for support and development: <lttng-dev@lists.lttng.org>.
.PP
You can find us on IRC server irc.oftc.net (OFTC) in #lttng.
.PP
.SH "THANKS"

.PP
Thanks to Yannick Brosseau without whom this project would never have been so
lean and mean! Also thanks to the Ericsson teams working on tracing which helped
us greatly with detailed bug reports and unusual test cases.

Thanks to our beloved packager Alexandre Montplaisir-Goncalves (Ubuntu and PPA
maintainer) and Jon Bernard for our Debian packages.

Special thanks to Michel Dagenais and the DORSAL laboratory at Polytechnique de
Montreal for the LTTng journey.
.PP
.SH "AUTHORS"

.PP
lttng-tools was originally written by Mathieu Desnoyers, Julien Desfossez and
David Goulet. More people have since contributed to it. It is currently
maintained by David Goulet <dgoulet@efficios.com>.
.PP
Commit	Line	Data
	1	.TH "LTTNG-SESSIOND" "8" "January 31, 2012" "" ""
	2
	3	.SH "NAME"
	4	lttng-sessiond \(em LTTng 2.x central tracing registry session daemon.
	5
	6	.SH "SYNOPSIS"
	7
	8	.PP
	9	.nf
	10	lttng-sessiond [OPTIONS]
	11	.fi
	12	.SH "DESCRIPTION"
	13
	14	.PP
	15	The LTTng project aims at providing highly efficient tracing tools for Linux.
	16	It's tracers help tracking down performance issues and debugging problems
	17	involving multiple concurrent processes and threads. Tracing across multiple
	18	systems is also possible.
	19
	20	The session daemon, acting as a tracing registry, allow you to interact with
	21	multiple tracers (kernel and user-space) inside the same container, a tracing
	22	session. Trace can be gathered from the kernel and/or instrumented applications
	23	(lttng-ust(3)). Aggregating those traces is done using a viewer, like the
	24	babeltrace(1) text viewer.
	25
	26	In order to trace the kernel, the session daemon needs to be running as root.
	27	LTTng provides the use of a \fBtracing group\fP (default: tracing). Whomever is
	28	in that group can interact with the root session daemon and thus trace the
	29	kernel. Session daemons can co-exist meaning that you can have a session daemon
	30	running as Alice that can be used to trace her applications along side with a
	31	root daemon or even a Bob daemon. We highly recommend to start the session
	32	daemon at boot time for stable and long term tracing.
	33
	34	The session daemon is in charge of managing trace data consumers by spawning
	35	them when the time has come. The user don't need to manage the lttng-consumerd.
	36	.SH "OPTIONS"
	37
	38	.PP
	39	This program follow the usual GNU command line syntax with long options starting with
	40	two dashes. Below is a summary of the available options.
	41	.PP
	42
	43	.TP
	44	.BR "-h, --help"
	45	Show summary of possible options and commands
	46	.TP
	47	.BR "-v, --verbose"
	48	Increase verbosity
	49
	50	There is three debugging level which will print on stderr. Maximum verbosity is
	51	\fB-vvv\fP.
	52	.TP
	53	.BR " --verbose-consumer"
	54	Verbose mode for consumer. Activate DBG() macro.
	55	.TP
	56	.BR "-d, --daemonize"
	57	Start as a daemon
	58	.TP
	59	.BR "-b, --background"
	60	Start as a daemon, keeping console open
	61	.TP
	62	.BR "-g, --group=NAME"
	63	Specify the tracing group name. (default: tracing)
	64	.TP
	65	.BR "-V, --version"
	66	Show version number
	67	.TP
	68	.BR "-S, --sig-parent"
	69	Send SIGUSR1 to parent pid to notify readiness.
	70
	71	This is used by \fBlttng(1)\fP to get notified when the session daemon is ready
	72	to accept command. When building a third party tool over liblttng-ctl, this option
	73	can be very handy to synchronize the control tool and the session daemon.
	74	.TP
	75	.BR "-q, --quiet"
	76	No output at all.
	77	.TP
	78	.BR " --no-kernel"
	79	No kernel tracer support
	80	.TP
	81	.BR "-c, --client-sock=PATH"
	82	Specify path for the client unix socket
	83	.TP
	84	.BR "-a, --apps-sock PATH"
	85	Specify path for apps unix socket
	86	.TP
	87	.BR " --kconsumerd-err-sock=PATH"
	88	Specify path for the kernel consumer error socket
	89	.TP
	90	.BR " --kconsumerd-cmd-sock=PATH
	91	Specify path for the kernel consumer command socket
	92	.TP
	93	.BR " --ustconsumerd32-err-sock=PATH
	94	Specify path for the 32-bit UST consumer error socket
	95	.TP
	96	.BR " --ustconsumerd64-err-sock=PATH
	97	Specify path for the 64-bit UST consumer error socket
	98	.TP
	99	.BR " --ustconsumerd32-cmd-sock=PATH
	100	Specify path for the 32-bit UST consumer command socket
	101	.TP
	102	.BR " --ustconsumerd64-cmd-sock=PATH
	103	Specify path for the 64-bit UST consumer command socket
	104	.TP
	105	.BR " --consumerd32-path=PATH
	106	Specify path for the 32-bit UST consumer daemon binary
	107	.TP
	108	.BR " --consumerd32-libdir=PATH
	109	Specify path for the 32-bit UST consumer daemon libraries
	110	.TP
	111	.BR " --consumerd64-path=PATH
	112	Specify path for the 64-bit UST consumer daemon binary
	113	.TP
	114	.BR " --consumerd64-libdir=PATH
	115	Specify path for the 64-bit UST consumer daemon libraries
	116	.SH "ENVIRONMENT VARIABLES"
	117
	118	.PP
	119	Note that all command line options will override environment variables.
	120	.PP
	121
	122	.PP
	123	.IP "LTTNG_CONSUMERD32_BIN"
	124	Specify the 32-bit consumer binary path. \fB--consumerd32-path\fP
	125	override this variable.
	126	.IP "LTTNG_CONSUMERD64_BIN"
	127	Specify the 64-bit consumer binary path. \fB--consumerd64-path\fP
	128	override this variable.
	129	.IP "LTTNG_CONSUMERD32_LIBDIR"
	130	Specifiy the 64-bit library path containing libconsumer.so.
	131	\fB--consumerd32-libdir\fP override this variable.
	132	.IP "LTTNG_CONSUMERD64_LIBDIR"
	133	Specifiy the 32-bit library path containing libconsumer.so.
	134	\fB--consumerd64-libdir\fP override this variable.
	135	.IP "LTTNG_DEBUG_NOCLONE"
	136	Debug-mode disabling use of clone/fork. Insecure, but required to allow
	137	debuggers to work with sessiond on some operating systems.
	138	.IP "LTTNG_APP_SOCKET_TIMEOUT"
	139	Control the timeout of application's socket when sending and receiving
	140	commands. Takes an integer parameter: the timeout value, in seconds.
	141	After this period of time, the application is unregistered by the
	142	session daemon. A value of 0 or -1 means an infinite timeout. Default
	143	value is 5 seconds.
	144	.IP "LTTNG_NETWORK_SOCKET_TIMEOUT"
	145	Control timeout of socket connection, receive and send. Takes an integer
	146	parameter: the timeout value, in milliseconds. A value of 0 or -1 uses
	147	the timeout of the operating system (this is the default).
	148	.SH "SEE ALSO"
	149
	150	.PP
	151	babeltrace(1), lttng-ust(3), lttng(1)
	152	.PP
	153
	154	.SH "LIMITATIONS"
	155
	156	.PP
	157	For unprivileged user running lttng-sessiond, the maximum number of file
	158	descriptors per process is usually 1024. This limits the number of traceable
	159	applications since for each instrumented application there is two file
	160	descriptors per-CPU and one more socktet for bidirectional communication.
	161
	162	For the root user, the limit is bumped to 65535. Future version will deal with
	163	this limitation.
	164	.PP
	165
	166	.SH "BUGS"
	167
	168	.PP
	169	No show stopper bugs are known yet in this version.
	170
	171	If you encounter any issues or usability problem, please report it on our
	172	mailing list <lttng-dev@lists.lttng.org> to help improve this project.
	173	.SH "CREDITS"
	174
	175	.PP
	176	lttng-sessiond is distributed under the GNU General Public License version 2. See the
	177	file COPYING for details.
	178	.PP
	179	A Web site is available at http://lttng.org for more information on the LTTng
	180	project.
	181	.PP
	182	You can also find our git tree at http://git.lttng.org.
	183	.PP
	184	Mailing lists for support and development: <lttng-dev@lists.lttng.org>.
	185	.PP
	186	You can find us on IRC server irc.oftc.net (OFTC) in #lttng.
	187	.PP
	188	.SH "THANKS"
	189
	190	.PP
	191	Thanks to Yannick Brosseau without whom this project would never have been so
	192	lean and mean! Also thanks to the Ericsson teams working on tracing which helped
	193	us greatly with detailed bug reports and unusual test cases.
	194
	195	Thanks to our beloved packager Alexandre Montplaisir-Goncalves (Ubuntu and PPA
	196	maintainer) and Jon Bernard for our Debian packages.
	197
	198	Special thanks to Michel Dagenais and the DORSAL laboratory at Polytechnique de
	199	Montreal for the LTTng journey.
	200	.PP
	201	.SH "AUTHORS"
	202
	203	.PP
	204	lttng-tools was originally written by Mathieu Desnoyers, Julien Desfossez and
	205	David Goulet. More people have since contributed to it. It is currently
	206	maintained by David Goulet <dgoulet@efficios.com>.
	207	.PP