doc/man/lttng-relayd.8.txt

   1 lttng-relayd(8)
   2 ===============
   3 :revdate: 5 June 2018
   4
   5
   6 NAME
   7 ----
   8 lttng-relayd - LTTng 2 relay daemon
   9
  10
  11 SYNOPSIS
  12 --------
  13 [verse]
  14 *lttng-relayd* [option:--background | option:--daemonize]
  15              [option:--control-port='URL'] [option:--data-port='URL'] [option:--live-port='URL']
  16              [option:--output='PATH'] [option:-v | option:-vv | option:-vvv]
  17              [option:--working-directory='PATH']
  18              [option:--group-output-by-session | option:--group-output-by-host]
  19
  20 DESCRIPTION
  21 -----------
  22 The https://lttng.org/[_Linux Trace Toolkit: next generation_] is an open
  23 source software package used for correlated tracing of the Linux kernel,
  24 user applications, and user libraries.
  25
  26 LTTng consists of Linux kernel modules (for Linux kernel tracing) and
  27 dynamically loaded libraries (for user application and library tracing).
  28
  29 The _LTTng relay daemon_ is responsible for receiving trace data from
  30 possibly remote LTTng session/consumer daemons and for writing it to
  31 the local file system. The relay daemon also accepts _LTTng live_
  32 connections from compatible viewers; this is the official approach to
  33 viewing LTTng events as they are emitted.
  34
  35 The relay daemon listens by default on all network interfaces to gather
  36 trace data, but only on localhost for LTTng live connections.
  37
  38 The relay daemon does not require any particular permissions, as long as
  39 it can write to the output directory and listen on the configured ports.
  40 If a user is within a secured network and/or has proper firewall
  41 settings, `lttng-relayd` can listen to LTTng live connections from _all_
  42 network interfaces by specifying
  43 +--live-port=tcp://{default_network_viewer_bind_address}:{default_network_viewer_port}+.
  44
  45 Once a trace has been streamed completely, the trace can be processed by
  46 any tool that can process an LTTng trace located on the local
  47 file system.
  48
  49
  50 [[output-directory]]
  51 Output directory
  52 ~~~~~~~~~~~~~~~~
  53 By default (option:--group-output-by-host), the relay daemon writes the traces
  54 to:
  55
  56 [verse]
  57 $LTTNG_HOME/lttng-traces/'HOSTNAME'/'SESSION'/'DOMAIN'
  58
  59 with:
  60
  61 'HOSTNAME'::
  62     Remote hostname.
  63
  64 'SESSION'::
  65     Full session name.
  66
  67 'DOMAIN'::
  68     Tracing domain.
  69
  70 You can group the output per session instead of per hostname with the
  71 option:--group-output-by-session option. This result in the following:
  72
  73 [verse]
  74
  75 $LTTNG_HOME/lttng-traces/'SESSION'/'HOST'/'DOMAIN'
  76
  77 You can override the default output directory prefix
  78 (`$LTTNG_HOME/lttng-traces`) with the option:--output option. The other
  79 parts depend on the remote configuration.
  80
  81 Grouping by session is not supported for peers with version inferior to 2.4.
  82 In such cases, the grouping of output for that particular peer will be per host
  83 (default).
  84
  85 A best effort backward compatibility is done for peers version greater or equal to
  86 2.4 and smaller than 2.11.
  87
  88 [[url-format]]
  89 URL format
  90 ~~~~~~~~~~
  91 The option:--control-port, option:--data-port, and option:--live-port
  92 options specify URLs.
  93
  94 The format of those URLs is:
  95
  96 [verse]
  97 tcp://('HOST' | 'IPADDR'):__PORT__
  98
  99 with:
 100
 101 ('HOST' | 'IPADDR')::
 102     Binding hostname or IP address (IPv6 address *must* be enclosed in
 103     brackets (`[` and `]`); see
 104     https://www.ietf.org/rfc/rfc2732.txt[RFC 2732]).
 105
 106 'PORT'::
 107     TCP port.
 108
 109
 110 OPTIONS
 111 -------
 112 Daemon
 113 ~~~~~~
 114 option:-b, option:--background::
 115     Start as Unix daemon, but keep file descriptors (console) open.
 116     Use the option:--daemonize option instead to close the file
 117     descriptors.
 118
 119 option:-d, option:--daemonize::
 120     Start as Unix daemon, and close file descriptors (console). Use the
 121     option:--background option instead to keep the file descriptors
 122     open.
 123
 124 option:-g 'GROUP', option:--group='GROUP'::
 125     Use 'GROUP' as Unix tracing group (default: `tracing`).
 126
 127 option:-o 'PATH', option:--output='PATH'::
 128     Set base directory of written trace data to 'PATH'.
 129 +
 130 See the <<output-directory,Output directory>> section above for more
 131 information.
 132
 133 option:-p, option:--group-output-by-host::
 134     Organize the output directory by host. Default behavior.
 135 +
 136 See the <<output-directory,Output directory>> section above for more
 137 information.
 138
 139 option:-s, option:--group-output-by-session::
 140     Organize the output directory by session.
 141 +
 142 See the <<output-directory,Output directory>> section above for more
 143 information.
 144
 145 option:-w 'PATH', option:--working-directory='PATH'::
 146     Set the working directory of the processes this relay daemon creates.
 147
 148 option:-v, option:--verbose::
 149     Increase verbosity.
 150 +
 151 Three levels of verbosity are available, which are triggered by
 152 appending additional `v` letters to the option
 153 (that is, `-vv` and `-vvv`).
 154
 155
 156 Ports
 157 ~~~~~
 158 See the <<url-format,URL format>> section above for more information
 159 about the syntax of the following options' 'URL' argument.
 160
 161 option:-C 'URL', option:--control-port='URL'::
 162     Listen to control data on URL 'URL' (default:
 163     +tcp://{default_network_control_bind_address}:{default_network_control_port}+).
 164
 165 option:-D 'URL', option:--data-port='URL'::
 166     Listen to trace data on URL 'URL' (default:
 167     +tcp://{default_network_data_bind_address}:{default_network_data_port}+).
 168
 169 option:-L 'URL', option:--live-port='URL'::
 170     Listen to LTTng live connections on URL 'URL'
 171     (default:
 172     +tcp://{default_network_viewer_bind_address}:{default_network_viewer_port}+).
 173
 174
 175 Program information
 176 ~~~~~~~~~~~~~~~~~~~
 177 option:-h, option:--help::
 178     Show help.
 179
 180 option:-V, option:--version::
 181     Show version.
 182
 183
 184 ENVIRONMENT VARIABLES
 185 ---------------------
 186 `LTTNG_ABORT_ON_ERROR`::
 187     Set to 1 to abort the process after the first error is encountered.
 188
 189 `LTTNG_NETWORK_SOCKET_TIMEOUT`::
 190     Socket connection, receive and send timeout (milliseconds). A value
 191     of 0 or -1 uses the timeout of the operating system (default).
 192
 193 `LTTNG_RELAYD_HEALTH`::
 194     Path to relay daemon health's socket.
 195
 196 `LTTNG_RELAYD_TCP_KEEP_ALIVE`::
 197     Set to 1 to enable TCP keep-alive.
 198 +
 199 The TCP keep-alive mechanism allows the detection of dead peers
 200 (man:lttng-sessiond(8)) in cases of unclean termination
 201 (for example, a hard reset) of a peer.
 202 +
 203 Supported on Linux and Solaris only. The default behaviour of the TCP
 204 keep-alive mechanism is OS-specific.
 205 +
 206 Search for `tcp_keepalive` in man:tcp(7) for more information.
 207
 208 `LTTNG_RELAYD_TCP_KEEP_ALIVE_ABORT_THRESHOLD`::
 209    The time threshold in seconds to abort a TCP connection after the keep-alive
 210    probing mechanism has failed.
 211 +
 212 Set to 0 or -1 to use the value chosen by the operating system (default).
 213 +
 214 Supported on Solaris 11 only.
 215 +
 216 Search for `tcp_keepalive_abort_threshold` in man:tcp(7) for more information.
 217
 218 `LTTNG_RELAYD_TCP_KEEP_ALIVE_IDLE_TIME`::
 219     Number of seconds a connection needs to be idle before TCP begins
 220     sending out keep-alive probes.
 221 +
 222 Set to 0 or -1 to use the value chosen by the operating system (default).
 223 +
 224 Supported on Linux and Solaris 11 only.
 225 +
 226 On Solaris{nbsp}11, the accepted values are -1, 0, and 10 to 864000.
 227 +
 228 Search for `tcp_keepalive_time` and `tcp_keepalive_interval`
 229 in man:tcp(7) on Solaris 11 for more information.
 230
 231 `LTTNG_RELAYD_TCP_KEEP_ALIVE_MAX_PROBE_COUNT`::
 232     Maximum number of TCP keep-alive probes to send before giving up and
 233     killing the connection if no response is obtained from the other end.
 234 +
 235 Set to 0 or -1 to use the value chosen by the operating system (default).
 236 +
 237 Supported on Linux only.
 238 +
 239 Search for `tcp_keepalive_probes` in man:tcp(7) for more information.
 240
 241 `LTTNG_RELAYD_TCP_KEEP_ALIVE_PROBE_INTERVAL`::
 242     Number of seconds between TCP keep-alive probes.
 243 +
 244 Set to 0 or -1 to use the value chosen by the operating system (default).
 245 +
 246 Supported on Linux only.
 247 +
 248 Search for `tcp_keepalive_intvl` in man:tcp(7) for more information.
 249
 250 `LTTNG_RELAYD_WORKING_DIRECTORY`::
 251     Working directory of the processes this relay daemon creates.
 252 +
 253 The option:--working-directory option overrides this variable.
 254
 255
 256 FILES
 257 -----
 258 `$LTTNG_HOME/.lttng`::
 259     User LTTng runtime and configuration directory.
 260
 261 `$LTTNG_HOME/lttng-traces`::
 262     Default output directory of LTTng traces. This can be overridden
 263     with the option:--output option.
 264
 265 NOTE: `$LTTNG_HOME` defaults to `$HOME` when not explicitly set.
 266
 267
 268 EXIT STATUS
 269 -----------
 270 *0*::
 271     Success
 272
 273 *1*::
 274     Error
 275
 276 *3*::
 277     Fatal error
 278
 279
 280 LIMITATIONS
 281 -----------
 282 As of this version, only the TCP protocol is supported for both control
 283 and data ports. In future versions, TCP will remain the sole available
 284 protocol for control data since those communications are low-volume and
 285 need absolute reliability; trace data could be carried over UDP.
 286
 287 For an unprivileged user running `lttng-relayd`, the maximum number of
 288 file descriptors per process is usually 1024. This limits the number of
 289 connections and opened trace files. This limit can be configured with
 290 *ulimit*(3).
 291
 292
 293 include::common-footer.txt[]
 294
 295
 296 SEE ALSO
 297 --------
 298 man:lttng(1),
 299 man:lttng-sessiond(8),
 300 man:lttng-crash(1),
 301 man:lttng-ust(3),
 302 man:babeltrace(1)