lttng-sessiond(8)
=================
:revdate: 21 April 2021
+:daemon-bin-name: lttng-sessiond
+:daemon-ini-section: sessiond
NAME
An LTTng session daemon, `lttng-sessiond`, is a program which:
-* Manages tracing sessions (see man:lttng-create(1) to learn more about
- tracing sessions).
+* Manages tracing sessions (see man:lttng-concepts(7) to learn more
+ about tracing sessions).
* Controls the various components (like tracers and consumer daemons) of
LTTng.
NOTE: The LTTng project recommends that you start the session daemon at
boot time for stable and long-term tracing.
+[NOTE]
+====
+For an unprivileged Unix 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 are two file descriptors per CPU as well as one
+socket for bidirectional communication.
-[[cfg]]
-Daemon configuration
-~~~~~~~~~~~~~~~~~~~~
-When you run `lttng-sessiond`, it configures itself from, in this order:
-
-. The INI configuration file +{system_lttng_conf}+, if any.
-
-. The INI configuration file `$LTTNG_HOME/.lttng/lttng.conf`, if any.
-+
-`$LTTNG_HOME` defaults to `$HOME`.
-
-. With the option:--config='PATH' option: the INI configuration file
- 'PATH'.
-
-. The command-line options.
-
-Each step can override a previous configuration property.
-
-In INI configuration files, the session daemon only reads the properties
-under the `sessiond` INI section. Each INI property is:
-
-Key::
- The long name of a command-line option to set (see the
- <<options,OPTIONS>> section below).
-
-Value::
- The selected command-line option accepts an argument:::
- Option argument (string).
+For the `root` user, the limit is usually 65,535.
+====
- The selected command-line option is a switch:::
- `true`::::
- `yes`::::
- `on`::::
- Enable the option.
- `false`::::
- `no`::::
- `off`::::
- Disable the option.
+include::common-daemon-cfg.txt[]
INI configuration file example:
[[options]]
OPTIONS
-------
-Daemon configuration
-~~~~~~~~~~~~~~~~~~~~
+General daemon configuration
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
option:-b, option:--background::
Start as a Unix daemon, but keep file descriptors (console) open.
+
For each 'PROBE' argument, load the LTTng kernel probe module
named ++lttng-probe-++__PROBE__++.ko++, in addition to loading the
default LTTng kernel probe modules.
++
+See also the `LTTNG_EXTRA_KMOD_PROBES` environment variable.
option:--kmod-probes='PROBE'[,'PROBE']...::
Only load, for each 'PROBE' argument, the LTTng kernel probe
module named ++lttng-probe-++__PROBE__++.ko++, instead of loading
the default LTTng kernel probe modules.
++
+See also the `LTTNG_KMOD_PROBES` environment variable.
option:--no-kernel::
Disable Linux kernel tracing.
option:--consumerd32-libdir='PATH'::
Set the 32-bit consumer daemon library directory to 'PATH'.
++
+See also the `LTTNG_CONSUMERD32_LIBDIR` environment variable.
option:--consumerd32-path='PATH'::
Set the 32-bit consumer daemon binary path to 'PATH'.
++
+See also the `LTTNG_CONSUMERD32_BIN` environment variable.
option:--consumerd64-libdir='PATH'::
Set the 64-bit consumer daemon library directory to 'PATH'.
++
+See also the `LTTNG_CONSUMERD64_LIBDIR` environment variable.
option:--consumerd64-path='PATH'::
Set the 64-bit consumer daemon binary path to 'PATH'.
++
+See also the `LTTNG_CONSUMERD32_BIN` environment variable.
option:--kconsumerd-cmd-sock='PATH'::
Set the command Unix socket path of the Linux kernel consumer daemon
`LTTNG_CONSUMERD32_BIN`::
32-bit consumer daemon binary path.
+
-The option:--consumerd32-path option overrides this variable.
+The option:--consumerd32-path option overrides this environment
+variable.
`LTTNG_CONSUMERD32_LIBDIR`::
32-bit consumer daemon library directory path.
+
-The option:--consumerd32-libdir option overrides this variable.
+The option:--consumerd32-libdir option overrides this environment
+variable.
`LTTNG_CONSUMERD64_BIN`::
64-bit consumer daemon binary path.
+
-The option:--consumerd64-path option overrides this variable.
+The option:--consumerd64-path option overrides this environment
+variable.
`LTTNG_CONSUMERD64_LIBDIR`::
64-bit consumer daemon library directory path.
+
-The option:--consumerd64-libdir option overrides this variable.
+The option:--consumerd64-libdir option overrides this environment
+variable.
`LTTNG_DEBUG_NOCLONE`::
Set to `1` to disable the use of man:clone(2)/man:fork(2).
+
-Setting this variable is considered insecure, but it's required to allow
-debuggers to work with `lttng-sessiond` on some operating systems.
+Setting this environment variable is considered insecure, but it's
+required to allow debuggers to work with `lttng-sessiond` on some
+operating systems.
`LTTNG_EXTRA_KMOD_PROBES`::
Extra LTTng kernel probe modules to load.
Fatal error
-LIMITATIONS
------------
-For an unprivileged Unix 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 are two file descriptors per CPU as well as one
-socket for bidirectional communication.
-
-For the `root` user, the limit is usually 65,535.
-
-
include::common-footer.txt[]
SEE ALSO
--------
-man:lttng(1)
+man:lttng(1),
+man:lttng-concepts(7)
projects / lttng-tools.git / blobdiff