[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 "    --agent-tcp-port"
Agent application registration TCP port (default: 5345)
.TP
.BR "    --kmod-probes=probe1, probe2, ..."
Specify the kernel modules containing LTTng probes to load by the session daemon.
Only the component name of the probe needs to be specified, e.g. to load the
lttng-probe-irq and lttng-probe-sched use: --kmod-probes="irq, sched".
.TP
.BR "    --extra-kmod-probes=probe1, probe2, ..."
Specify extra kernel modules containing LTTng probes to be loaded by the session
daemon. The list follows the format of the \fB--kmod-probes\fP option.
This list is appended to the list provided by \fB--kmod-probes\fP or, if
\fB--kmod-probes\fP is missing, to the default list of probes.
.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
.TP
.BR "-l, --load PATH
Specify path from which to automatically load session configuration(s).

.SH "LOADING SESSIONS"

.PP
By default, the session daemon tries to load session configuration(s) located
in the user default directory \fB~/.lttng/sessions/auto/\fP and in the system
wide one in \fB/etc/lttng/sessions/auto/\fP. Note that the directory containing
the session's configuration and lttng-sessiond MUST have the same UID for them
to be automatically loaded.

Specifying a path with \-l, \-\-load PATH overrides the default directory and
UID check. The lttng-sessiond will simply check if it's accessible and try to
load every session file in it.
.PP

.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"
Specify the 64-bit library path containing libconsumer.so.
\fB--consumerd32-libdir\fP override this variable.
.IP "LTTNG_CONSUMERD64_LIBDIR"
Specify 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).
.IP "LTTNG_SESSION_CONFIG_XSD_PATH"
Specify the path that contains the XML session configuration schema (xsd).
.IP "LTTNG_KMOD_PROBES"
Specify the kernel modules probes that should be loaded by the session daemon.
.IP "LTTNG_EXTRA_KMOD_PROBES"
Specify extra kernel modules probes that should be loaded by the session daemon.
.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 socket 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 " --agent-tcp-port"
	82	Agent application registration TCP port (default: 5345)
	83	.TP
	84	.BR " --kmod-probes=probe1, probe2, ..."
	85	Specify the kernel modules containing LTTng probes to load by the session daemon.
	86	Only the component name of the probe needs to be specified, e.g. to load the
	87	lttng-probe-irq and lttng-probe-sched use: --kmod-probes="irq, sched".
	88	.TP
	89	.BR " --extra-kmod-probes=probe1, probe2, ..."
	90	Specify extra kernel modules containing LTTng probes to be loaded by the session
	91	daemon. The list follows the format of the \fB--kmod-probes\fP option.
	92	This list is appended to the list provided by \fB--kmod-probes\fP or, if
	93	\fB--kmod-probes\fP is missing, to the default list of probes.
	94	.TP
	95	.BR "-c, --client-sock=PATH"
	96	Specify path for the client unix socket
	97	.TP
	98	.BR "-a, --apps-sock PATH"
	99	Specify path for apps unix socket
	100	.TP
	101	.BR " --kconsumerd-err-sock=PATH"
	102	Specify path for the kernel consumer error socket
	103	.TP
	104	.BR " --kconsumerd-cmd-sock=PATH
	105	Specify path for the kernel consumer command socket
	106	.TP
	107	.BR " --ustconsumerd32-err-sock=PATH
	108	Specify path for the 32-bit UST consumer error socket
	109	.TP
	110	.BR " --ustconsumerd64-err-sock=PATH
	111	Specify path for the 64-bit UST consumer error socket
	112	.TP
	113	.BR " --ustconsumerd32-cmd-sock=PATH
	114	Specify path for the 32-bit UST consumer command socket
	115	.TP
	116	.BR " --ustconsumerd64-cmd-sock=PATH
	117	Specify path for the 64-bit UST consumer command socket
	118	.TP
	119	.BR " --consumerd32-path=PATH
	120	Specify path for the 32-bit UST consumer daemon binary
	121	.TP
	122	.BR " --consumerd32-libdir=PATH
	123	Specify path for the 32-bit UST consumer daemon libraries
	124	.TP
	125	.BR " --consumerd64-path=PATH
	126	Specify path for the 64-bit UST consumer daemon binary
	127	.TP
	128	.BR " --consumerd64-libdir=PATH
	129	Specify path for the 64-bit UST consumer daemon libraries
	130	.TP
	131	.BR "-l, --load PATH
	132	Specify path from which to automatically load session configuration(s).
	133
	134	.SH "LOADING SESSIONS"
	135
	136	.PP
	137	By default, the session daemon tries to load session configuration(s) located
	138	in the user default directory \fB~/.lttng/sessions/auto/\fP and in the system
	139	wide one in \fB/etc/lttng/sessions/auto/\fP. Note that the directory containing
	140	the session's configuration and lttng-sessiond MUST have the same UID for them
	141	to be automatically loaded.
	142
	143	Specifying a path with \-l, \-\-load PATH overrides the default directory and
	144	UID check. The lttng-sessiond will simply check if it's accessible and try to
	145	load every session file in it.
	146	.PP
	147
	148	.SH "ENVIRONMENT VARIABLES"
	149
	150	.PP
	151	Note that all command line options will override environment variables.
	152	.PP
	153
	154	.PP
	155	.IP "LTTNG_CONSUMERD32_BIN"
	156	Specify the 32-bit consumer binary path. \fB--consumerd32-path\fP
	157	override this variable.
	158	.IP "LTTNG_CONSUMERD64_BIN"
	159	Specify the 64-bit consumer binary path. \fB--consumerd64-path\fP
	160	override this variable.
	161	.IP "LTTNG_CONSUMERD32_LIBDIR"
	162	Specify the 64-bit library path containing libconsumer.so.
	163	\fB--consumerd32-libdir\fP override this variable.
	164	.IP "LTTNG_CONSUMERD64_LIBDIR"
	165	Specify the 32-bit library path containing libconsumer.so.
	166	\fB--consumerd64-libdir\fP override this variable.
	167	.IP "LTTNG_DEBUG_NOCLONE"
	168	Debug-mode disabling use of clone/fork. Insecure, but required to allow
	169	debuggers to work with sessiond on some operating systems.
	170	.IP "LTTNG_APP_SOCKET_TIMEOUT"
	171	Control the timeout of application's socket when sending and receiving
	172	commands. Takes an integer parameter: the timeout value, in seconds.
	173	After this period of time, the application is unregistered by the
	174	session daemon. A value of 0 or -1 means an infinite timeout. Default
	175	value is 5 seconds.
	176	.IP "LTTNG_NETWORK_SOCKET_TIMEOUT"
	177	Control timeout of socket connection, receive and send. Takes an integer
	178	parameter: the timeout value, in milliseconds. A value of 0 or -1 uses
	179	the timeout of the operating system (this is the default).
	180	.IP "LTTNG_SESSION_CONFIG_XSD_PATH"
	181	Specify the path that contains the XML session configuration schema (xsd).
	182	.IP "LTTNG_KMOD_PROBES"
	183	Specify the kernel modules probes that should be loaded by the session daemon.
	184	.IP "LTTNG_EXTRA_KMOD_PROBES"
	185	Specify extra kernel modules probes that should be loaded by the session daemon.
	186	.SH "SEE ALSO"
	187
	188	.PP
	189	babeltrace(1), lttng-ust(3), lttng(1)
	190	.PP
	191
	192	.SH "LIMITATIONS"
	193
	194	.PP
	195	For unprivileged user running lttng-sessiond, the maximum number of file
	196	descriptors per process is usually 1024. This limits the number of traceable
	197	applications since for each instrumented application there is two file
	198	descriptors per-CPU and one more socket for bidirectional communication.
	199
	200	For the root user, the limit is bumped to 65535. Future version will deal with
	201	this limitation.
	202	.PP
	203
	204	.SH "BUGS"
	205
	206	.PP
	207	No show stopper bugs are known yet in this version.
	208
	209	If you encounter any issues or usability problem, please report it on our
	210	mailing list <lttng-dev@lists.lttng.org> to help improve this project.
	211	.SH "CREDITS"
	212
	213	.PP
	214	lttng-sessiond is distributed under the GNU General Public License version 2. See the
	215	file COPYING for details.
	216	.PP
	217	A Web site is available at http://lttng.org for more information on the LTTng
	218	project.
	219	.PP
	220	You can also find our git tree at http://git.lttng.org.
	221	.PP
	222	Mailing lists for support and development: <lttng-dev@lists.lttng.org>.
	223	.PP
	224	You can find us on IRC server irc.oftc.net (OFTC) in #lttng.
	225	.PP
	226	.SH "THANKS"
	227
	228	.PP
	229	Thanks to Yannick Brosseau without whom this project would never have been so
	230	lean and mean! Also thanks to the Ericsson teams working on tracing which helped
	231	us greatly with detailed bug reports and unusual test cases.
	232
	233	Thanks to our beloved packager Alexandre Montplaisir-Goncalves (Ubuntu and PPA
	234	maintainer) and Jon Bernard for our Debian packages.
	235
	236	Special thanks to Michel Dagenais and the DORSAL laboratory at Polytechnique de
	237	Montreal for the LTTng journey.
	238	.PP
	239	.SH "AUTHORS"
	240
	241	.PP
	242	lttng-tools was originally written by Mathieu Desnoyers, Julien Desfossez and
	243	David Goulet. More people have since contributed to it. It is currently
	244	maintained by David Goulet <dgoulet@efficios.com>.
	245	.PP