doc/man/lttng-sessiond.8

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