e70242d46170ff779487d800fd010e14e1ca07bf
[lttng-tools.git] / 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)
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