32eccbeda142b34a9de22ece4f2d5b64cf2f3155
[lttng-tools.git] / 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:--live-port='URL']
15 [option:--output='PATH'] [option:-v | option:-vv | option:-vvv]
16
17
18 DESCRIPTION
19 -----------
20 The http://lttng.org/[_Linux Trace Toolkit: next generation_] is an open
21 source software package used for correlated tracing of the Linux kernel,
22 user applications, and user libraries.
23
24 LTTng consists of Linux kernel modules (for Linux kernel tracing) and
25 dynamically loaded libraries (for user application and library tracing).
26
27 The _LTTng relay daemon_ is responsible for receiving trace data from
28 possibly remote LTTng session/consumer daemons and for writing it to
29 the local file system. The relay daemon also accepts _LTTng live_
30 connections from compatible viewers; this is the official approach to
31 viewing LTTng events as they are emitted.
32
33 The relay daemon listens by default on all network interfaces to gather
34 trace data, but only on localhost for LTTng live connections.
35
36 The relay daemon does not require any particular permissions, as long as
37 it can write to the output directory and listen on the configured ports.
38 If a user is within a secured network and/or has proper firewall
39 settings, `lttng-relayd` can listen to LTTng live connections from _all_
40 network interfaces by specifying `--live-port=tcp://0.0.0.0:5344`.
41
42 Once a trace has been streamed completely, the trace can be processed by
43 any tool that can process an LTTng trace located on the local
44 file system.
45
46
47 [[output-directory]]
48 Output directory
49 ~~~~~~~~~~~~~~~~
50 By default, the relay daemon writes the traces to:
51
52 [verse]
53 $HOME/lttng-traces/'HOSTNAME'/'SESSION'/'DOMAIN'
54
55 with:
56
57 'HOSTNAME'::
58 Remote hostname.
59
60 'SESSION'::
61 Full session name.
62
63 'DOMAIN'::
64 Tracing domain.
65
66 You can override the default output directory prefix
67 (`$HOME/lttng-traces`) with the option:--output option. The other
68 parts depend on the remote configuration.
69
70
71 [[url-format]]
72 URL format
73 ~~~~~~~~~~
74 The option:--control-port, option:--data-port, and option:--live-port
75 options specify URLs.
76
77 The format of those URLs is:
78
79 [verse]
80 tcp://('HOST' | 'IPADDR'):__PORT__
81
82 with:
83
84 ('HOST' | 'IPADDR')::
85 Binding hostname or IP address (IPv6 address *must* be enclosed in
86 brackets (`[` and `]`); see
87 https://www.ietf.org/rfc/rfc2732.txt[RFC 2732]).
88
89 'PORT'::
90 TCP port.
91
92
93 OPTIONS
94 -------
95 Daemon
96 ~~~~~~
97 option:-b, option:--background::
98 Start as Unix daemon, but keep file descriptors (console) open.
99 Use the option:--daemonize option instead to close the file
100 descriptors.
101
102 option:-d, option:--daemonize::
103 Start as Unix daemon, and close file descriptors (console). Use the
104 option:--background option instead to keep the file descriptors
105 open.
106
107 option:-g, option:--group='GROUP'::
108 Use 'GROUP' as Unix tracing group (default: `tracing`).
109
110 option:-o, option:--output='PATH'::
111 Set base directory of written trace data to 'PATH'.
112 +
113 See the <<output-directory,Output directory>> section above for more
114 information.
115
116 option:-v, option:--verbose::
117 Increase verbosity.
118 +
119 Three levels of verbosity are available, which are triggered by
120 appending additional `v` letters to the option
121 (that is, `-vv` and `-vvv`).
122
123
124 Ports
125 ~~~~~
126 See the <<url-format,URL format>> section above for more information
127 about the syntax of the following options' 'URL' argument.
128
129 option:-C, option:--control-port='URL'::
130 Listen to control data on URL 'URL' (default: `tcp://0.0.0.0:5342`).
131
132 option:-D, option:--data-port='URL'::
133 Listen to trace data on URL 'URL' (default: `tcp://0.0.0.0:5343`).
134
135 option:-L, option:--live-port='URL'::
136 Listen to LTTng live connections on URL 'URL'
137 (default: `tcp://0.0.0.0:5344`).
138
139
140 Program information
141 ~~~~~~~~~~~~~~~~~~~
142 option:-h, option:--help::
143 Show help.
144
145 option:-V, option:--version::
146 Show version.
147
148
149 ENVIRONMENT VARIABLES
150 ---------------------
151 `LTTNG_NETWORK_SOCKET_TIMEOUT`::
152 Socket connection, receive and send timeout (milliseconds). A value
153 of 0 or -1 uses the timeout of the operating system (default).
154
155 `LTTNG_RELAYD_HEALTH`::
156 Path to relay daemon health's socket.
157
158
159 EXIT STATUS
160 -----------
161 *0*::
162 Success
163
164 *1*::
165 Error
166
167 *3*::
168 Fatal error
169
170
171 LIMITATIONS
172 -----------
173 As of this version, only the TCP protocol is supported for both control
174 and data ports. In future versions, TCP will remain the sole available
175 protocol for control data since those communications are low-volume and
176 need absolute reliability; trace data could be carried over UDP.
177
178 For an unprivileged user running `lttng-relayd`, the maximum number of
179 file descriptors per process is usually 1024. This limits the number of
180 connections and opened trace files. This limit can be configured with
181 *ulimit*(3).
182
183
184 include::common-footer.txt[]
185
186
187 SEE ALSO
188 --------
189 linklttng:lttng(1),
190 linklttng:lttng-sessiond(8),
191 linklttng:lttng-crash(1),
192 linklttng:lttng-ust(3),
193 linklttng:babeltrace(1)
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