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:--fd-pool-size='COUNT']
  16              [option:--live-port='URL'] [option:--output='PATH']
  17              [option:-v | option:-vv | option:-vvv] [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://0.0.0.0:{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:--fd-pool-size='SIZE'::
 125     Set the size of the file descriptor pool. This effectively sets a
 126     limit on the number of file descriptors that may be kept open
 127     simultaneously by the daemon (default: the soft `RLIMIT_NOFILE` resource
 128     limit of the process).
 129
 130 option:-g 'GROUP', option:--group='GROUP'::
 131     Use 'GROUP' as Unix tracing group (default: `tracing`).
 132
 133 option:-o 'PATH', option:--output='PATH'::
 134     Set base directory of written trace data to 'PATH'.
 135 +
 136 See the <<output-directory,Output directory>> section above for more
 137 information.
 138
 139 option:-p, option:--group-output-by-host::
 140     Organize the output directory by host. Default behavior.
 141 +
 142 See the <<output-directory,Output directory>> section above for more
 143 information.
 144
 145 option:-s, option:--group-output-by-session::
 146     Organize the output directory by session.
 147 +
 148 See the <<output-directory,Output directory>> section above for more
 149 information.
 150
 151 option:-w 'PATH', option:--working-directory='PATH'::
 152     Set the working directory of the processes this relay daemon creates.
 153
 154 option:-v, option:--verbose::
 155     Increase verbosity.
 156 +
 157 Three levels of verbosity are available, which are triggered by
 158 appending additional `v` letters to the option
 159 (that is, `-vv` and `-vvv`).
 160
 161
 162 Ports
 163 ~~~~~
 164 See the <<url-format,URL format>> section above for more information
 165 about the syntax of the following options' 'URL' argument.
 166
 167 option:-C 'URL', option:--control-port='URL'::
 168     Listen to control data on URL 'URL' (default:
 169     +tcp://{default_network_control_bind_address}:{default_network_control_port}+).
 170
 171 option:-D 'URL', option:--data-port='URL'::
 172     Listen to trace data on URL 'URL' (default:
 173     +tcp://{default_network_data_bind_address}:{default_network_data_port}+).
 174
 175 option:-L 'URL', option:--live-port='URL'::
 176     Listen to LTTng live connections on URL 'URL'
 177     (default:
 178     +tcp://{default_network_viewer_bind_address}:{default_network_viewer_port}+).
 179
 180
 181 Program information
 182 ~~~~~~~~~~~~~~~~~~~
 183 option:-h, option:--help::
 184     Show help.
 185
 186 option:-V, option:--version::
 187     Show version.
 188
 189
 190 ENVIRONMENT VARIABLES
 191 ---------------------
 192 `LTTNG_ABORT_ON_ERROR`::
 193     Set to 1 to abort the process after the first error is encountered.
 194
 195 `LTTNG_NETWORK_SOCKET_TIMEOUT`::
 196     Socket connection, receive and send timeout (milliseconds). A value
 197     of 0 or -1 uses the timeout of the operating system (default).
 198
 199 `LTTNG_RELAYD_DISALLOW_CLEAR`::
 200     Set to 1 to disallow the use of lttng-clear(1) on sessions collected by
 201     this relay daemon.
 202
 203 `LTTNG_RELAYD_HEALTH`::
 204     Path to relay daemon health's socket.
 205
 206 `LTTNG_RELAYD_TCP_KEEP_ALIVE`::
 207     Set to 1 to enable TCP keep-alive.
 208 +
 209 The TCP keep-alive mechanism allows the detection of dead peers
 210 (man:lttng-sessiond(8)) in cases of unclean termination
 211 (for example, a hard reset) of a peer.
 212 +
 213 Supported on Linux and Solaris only. The default behaviour of the TCP
 214 keep-alive mechanism is OS-specific.
 215 +
 216 Search for `tcp_keepalive` in man:tcp(7) for more information.
 217
 218 `LTTNG_RELAYD_TCP_KEEP_ALIVE_ABORT_THRESHOLD`::
 219    The time threshold in seconds to abort a TCP connection after the keep-alive
 220    probing mechanism has failed.
 221 +
 222 Set to 0 or -1 to use the value chosen by the operating system (default).
 223 +
 224 Supported on Solaris 11 only.
 225 +
 226 Search for `tcp_keepalive_abort_threshold` in man:tcp(7) for more information.
 227
 228 `LTTNG_RELAYD_TCP_KEEP_ALIVE_IDLE_TIME`::
 229     Number of seconds a connection needs to be idle before TCP begins
 230     sending out keep-alive probes.
 231 +
 232 Set to 0 or -1 to use the value chosen by the operating system (default).
 233 +
 234 Supported on Linux and Solaris 11 only.
 235 +
 236 On Solaris{nbsp}11, the accepted values are -1, 0, and 10 to 864000.
 237 +
 238 Search for `tcp_keepalive_time` and `tcp_keepalive_interval`
 239 in man:tcp(7) on Solaris 11 for more information.
 240
 241 `LTTNG_RELAYD_TCP_KEEP_ALIVE_MAX_PROBE_COUNT`::
 242     Maximum number of TCP keep-alive probes to send before giving up and
 243     killing the connection if no response is obtained from the other end.
 244 +
 245 Set to 0 or -1 to use the value chosen by the operating system (default).
 246 +
 247 Supported on Linux only.
 248 +
 249 Search for `tcp_keepalive_probes` in man:tcp(7) for more information.
 250
 251 `LTTNG_RELAYD_TCP_KEEP_ALIVE_PROBE_INTERVAL`::
 252     Number of seconds between TCP keep-alive probes.
 253 +
 254 Set to 0 or -1 to use the value chosen by the operating system (default).
 255 +
 256 Supported on Linux only.
 257 +
 258 Search for `tcp_keepalive_intvl` in man:tcp(7) for more information.
 259
 260 `LTTNG_RELAYD_WORKING_DIRECTORY`::
 261     Working directory of the processes this relay daemon creates.
 262 +
 263 The option:--working-directory option overrides this variable.
 264
 265
 266 FILES
 267 -----
 268 `$LTTNG_HOME/.lttng`::
 269     User LTTng runtime and configuration directory.
 270
 271 `$LTTNG_HOME/lttng-traces`::
 272     Default output directory of LTTng traces. This can be overridden
 273     with the option:--output option.
 274
 275 NOTE: `$LTTNG_HOME` defaults to `$HOME` when not explicitly set.
 276
 277
 278 EXIT STATUS
 279 -----------
 280 *0*::
 281     Success
 282
 283 *1*::
 284     Error
 285
 286 *3*::
 287     Fatal error
 288
 289
 290 LIMITATIONS
 291 -----------
 292 As of this version, only the TCP protocol is supported for both control
 293 and data ports. In future versions, TCP will remain the sole available
 294 protocol for control data since those communications are low-volume and
 295 need absolute reliability; trace data could be carried over UDP.
 296
 297 For an unprivileged user running `lttng-relayd`, the maximum number of
 298 file descriptors per process is usually 1024. This limits the number of
 299 connections and opened trace files. This limit can be configured with
 300 *ulimit*(3).
 301
 302
 303 include::common-footer.txt[]
 304
 305
 306 SEE ALSO
 307 --------
 308 man:lttng(1),
 309 man:lttng-sessiond(8),
 310 man:lttng-crash(1),
 311 man:lttng-ust(3),
 312 man:babeltrace(1)