doc/man/lttng-relayd.8.txt

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