lttng-sessiond(8)
=================
+:revdate: 17 September 2018
NAME
DESCRIPTION
-----------
-The http://lttng.org/[_Linux Trace Toolkit: next generation_] is an open
+The https://lttng.org/[_Linux Trace Toolkit: next generation_] is an open
source software package used for correlated tracing of the Linux kernel,
user applications, and user libraries.
to interact with multiple tracers (kernel and user space) within the
same container, a _tracing session_. Traces can be gathered from the
Linux kernel and/or from instrumented applications (see
-linklttng:lttng-ust(3)). You can aggregate and read the events of LTTng
-traces using linklttng:babeltrace(1).
+man:lttng-ust(3)). You can aggregate and read the events of LTTng
+traces using man:babeltrace2(1).
To trace the Linux kernel, the session daemon needs to be running as
`root`. LTTng uses a _tracing group_ to allow specific users to interact
for stable and long-term tracing.
-Loading tracing session configurations
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-By default, the LTTng session daemon tries to load tracing session
-configurations located in the user default directory
-`$HOME/.lttng/sessions` and in the system one, `/etc/lttng/sessions`.
+Automatic loading of tracing session configurations
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+When the session daemon starts, it automatically loads session
+configuration files.
+
+The following directories are searched, non-recursively, in this order
+for configuration files to load on launch:
+
+. `$LTTNG_HOME/.lttng/sessions/auto` (`$LTTNG_HOME` defaults to `$HOME`)
+. +{system_sessions_auto_dir}+
+
Note that both the directory containing the tracing session
-configurations and the session daemon binary _must_ have the same UID
+configurations _and_ the session daemon binary _must_ share the same UID
for the configurations to be automatically loaded.
-Specifying a path with the option:--load option overrides the default
-directory _and_ the UID check. The session daemon simply checks if the
-path is accessible and tries to load every tracing session configuration
-in it.
+The option:--load option overrides the default directories _and_ the UID
+check. The session daemon simply checks if the path is accessible and
+tries to load every tracing session configuration in it. When this
+option is specified, the default directories are :not: searched for
+configuration files. When the option is not specified, _both_ default
+directories are searched for configuration files.
+
+If the option:--load option's argument is a directory, then all the
+tracing session configurations found in all the files in this directory
+are loaded. If the argument is a file, then all the tracing session
+configurations found in this file are loaded.
OPTIONS
Use the option:--daemonize option instead to close the file
descriptors.
+option:-f, option:--config='PATH'::
+ Load session daemon configuration from path 'PATH'.
+
option:-d, option:--daemonize::
Start as Unix daemon, and close file descriptors (console). Use the
option:--background option instead to keep the file descriptors
open.
-option:-f, option:--config='PATH'::
- Load session daemon configuration from path 'PATH'.
-
option:-g, option:--group='GROUP'::
Use 'GROUP' as Unix tracing group (default: `tracing`).
option:-l, option:--load='PATH'::
- Automatically load tracing session configurations from path 'PATH'.
+ Automatically load tracing session configurations from 'PATH',
+ either a directory or a file, instead of loading them from the
+ default search directories.
option:-S, option:--sig-parent::
Send `SIGUSR1` to parent process to notify readiness.
+
-NOTE: This is used by linklttng:lttng(1) to get notified when the
+NOTE: This is used by man:lttng(1) to get notified when the
session daemon is ready to accept commands. When building a third party
tool on liblttng-ctl, this option can be very handy to synchronize the
control tool and the session daemon.
~~~~~~~~~~~~~~~
option:--agent-tcp-port='PORT'::
Listen on TCP port 'PORT' for agent application registrations
- (default: 5345).
+ (default: a port within the range
+ [{default_agent_tcp_port_range_begin},{nbsp}{default_agent_tcp_port_range_end}]).
-option:-a, option:--apps-sock='PATH'::
+option:-a 'PATH', option:--apps-sock='PATH'::
Set application Unix socket path to 'PATH'.
-option:-c, option:--client-sock='PATH'::
+option:-c 'PATH', option:--client-sock='PATH'::
Set client Unix socket path to 'PATH'.
option:--consumerd32-libdir='PATH'::
Note that command-line options override their equivalent environment
variable.
+`LTTNG_ABORT_ON_ERROR`::
+ Set to 1 to abort the process after the first error is encountered.
+
`LTTNG_APP_SOCKET_TIMEOUT`::
Application socket's timeout (seconds) when sending/receiving
commands. 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: 5.
+ Default value: {default_app_socket_rw_timeout}.
`LTTNG_CONSUMERD32_BIN`::
32-bit consumer daemon binary path.
Tracing session configuration XML schema definition (XSD) path.
+FILES
+-----
+`$LTTNG_HOME/.lttng`::
+ User LTTng runtime and configuration directory.
+
+`$LTTNG_HOME/lttng-traces`::
+ Default output directory of LTTng traces. This can be overridden
+ with the nloption:--output option of the man:lttng-create(1)
+ command.
+
+`$LTTNG_HOME/.lttng/sessions/auto`::
+ Directory from which user tracing configuration files are
+ automatically loaded when the session daemon starts (see
+ man:lttng-save(1) and man:lttng-load(1) for saving
+ and loading tracing sessions).
+
++{system_sessions_auto_dir}+::
+ Directory from which system-wide tracing configuration files are
+ automatically loaded when the session daemon starts (see
+ man:lttng-save(1) and man:lttng-load(1) for saving
+ and loading tracing sessions).
+
+`$LTTNG_HOME/.lttng/lttng.conf`::
+ Default location of the session daemon configuration file (see the
+ option:--config option).
+
++{system_lttng_conf}+::
+ System-wide location of the session daemon configuration file (see
+ the option:--config option).
+
+NOTE: `$LTTNG_HOME` defaults to `$HOME` when not explicitly set.
+
+
EXIT STATUS
-----------
*0*::
SEE ALSO
--------
-linklttng:lttng(1),
-linklttng:lttng-relayd(8),
-linklttng:lttng-crash(1),
-linklttng:lttng-ust(3),
-linklttng:babeltrace(1)
+man:lttng(1),
+man:lttng-relayd(8),
+man:lttng-crash(1),
+man:lttng-ust(3),
+man:babeltrace2(1)
projects / lttng-tools.git / blobdiff