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f5595c32 PP |
1 | lttng-relayd(8) |
2 | =============== | |
4605890e | 3 | :revdate: 5 June 2018 |
f5595c32 PP |
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] | |
6ab3f69a | 17 | [option:--working-directory='PATH'] |
04dedfc0 | 18 | [option:--group-output-by-session | option:--group-output-by-host] |
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19 | |
20 | DESCRIPTION | |
21 | ----------- | |
a18d9544 | 22 | The https://lttng.org/[_Linux Trace Toolkit: next generation_] is an open |
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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_ | |
c93eadad PP |
42 | network interfaces by specifying |
43 | +--live-port=tcp://{default_network_viewer_bind_address}:{default_network_viewer_port}+. | |
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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 | ~~~~~~~~~~~~~~~~ | |
04dedfc0 JR |
53 | By default (option:--group-output-by-host), the relay daemon writes the traces |
54 | to: | |
f5595c32 PP |
55 | |
56 | [verse] | |
2ff6d569 | 57 | $LTTNG_HOME/lttng-traces/'HOSTNAME'/'SESSION'/'DOMAIN' |
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58 | |
59 | with: | |
60 | ||
61 | 'HOSTNAME':: | |
62 | Remote hostname. | |
63 | ||
64 | 'SESSION':: | |
65 | Full session name. | |
66 | ||
67 | 'DOMAIN':: | |
68 | Tracing domain. | |
69 | ||
04dedfc0 JR |
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 | $LTTNG_HOME/lttng-traces/'SESSION'/'HOST'/'DOMAIN' | |
76 | ||
f5595c32 | 77 | You can override the default output directory prefix |
2ff6d569 | 78 | (`$LTTNG_HOME/lttng-traces`) with the option:--output option. The other |
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79 | parts depend on the remote configuration. |
80 | ||
04dedfc0 JR |
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. | |
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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 | ||
59b19c3c | 124 | option:-g 'GROUP', option:--group='GROUP':: |
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125 | Use 'GROUP' as Unix tracing group (default: `tracing`). |
126 | ||
59b19c3c | 127 | option:-o 'PATH', option:--output='PATH':: |
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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 | ||
04dedfc0 JR |
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 | ||
6ab3f69a JR |
145 | option:-w 'PATH', option:--working-directory='PATH':: |
146 | Set the working directory of the processes this relay daemon creates. | |
147 | ||
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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 | ||
59b19c3c | 161 | option:-C 'URL', option:--control-port='URL':: |
c93eadad PP |
162 | Listen to control data on URL 'URL' (default: |
163 | +tcp://{default_network_control_bind_address}:{default_network_control_port}+). | |
f5595c32 | 164 | |
59b19c3c | 165 | option:-D 'URL', option:--data-port='URL':: |
c93eadad PP |
166 | Listen to trace data on URL 'URL' (default: |
167 | +tcp://{default_network_data_bind_address}:{default_network_data_port}+). | |
f5595c32 | 168 | |
59b19c3c | 169 | option:-L 'URL', option:--live-port='URL':: |
f5595c32 | 170 | Listen to LTTng live connections on URL 'URL' |
c93eadad PP |
171 | (default: |
172 | +tcp://{default_network_viewer_bind_address}:{default_network_viewer_port}+). | |
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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 | --------------------- | |
9bbd8e06 MD |
186 | `LTTNG_ABORT_ON_ERROR`:: |
187 | Set to 1 to abort the process after the first error is encountered. | |
188 | ||
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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 | ||
e0512bf5 JR |
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 | ||
508a802c JR |
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 | ||
f5595c32 | 255 | |
900690ca PP |
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 | ||
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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 | -------- | |
7c1a4458 PP |
298 | man:lttng(1), |
299 | man:lttng-sessiond(8), | |
300 | man:lttng-crash(1), | |
301 | man:lttng-ust(3), | |
302 | man:babeltrace(1) |