7 lttng-relayd - LTTng 2 relay daemon
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 [option:--working-directory='PATH']
21 The http://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.
25 LTTng consists of Linux kernel modules (for Linux kernel tracing) and
26 dynamically loaded libraries (for user application and library tracing).
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.
34 The relay daemon listens by default on all network interfaces to gather
35 trace data, but only on localhost for LTTng live connections.
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}+.
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
52 By default, the relay daemon writes the traces to:
55 $LTTNG_HOME/lttng-traces/'HOSTNAME'/'SESSION'/'DOMAIN'
68 You can override the default output directory prefix
69 (`$LTTNG_HOME/lttng-traces`) with the option:--output option. The other
70 parts depend on the remote configuration.
76 The option:--control-port, option:--data-port, and option:--live-port
79 The format of those URLs is:
82 tcp://('HOST' | 'IPADDR'):__PORT__
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]).
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
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
109 option:-g 'GROUP', option:--group='GROUP'::
110 Use 'GROUP' as Unix tracing group (default: `tracing`).
112 option:-o 'PATH', option:--output='PATH'::
113 Set base directory of written trace data to 'PATH'.
115 See the <<output-directory,Output directory>> section above for more
118 option:-w 'PATH', option:--working-directory='PATH'::
119 Set the working directory of the processes this relay daemon creates.
121 option:-v, option:--verbose::
124 Three levels of verbosity are available, which are triggered by
125 appending additional `v` letters to the option
126 (that is, `-vv` and `-vvv`).
131 See the <<url-format,URL format>> section above for more information
132 about the syntax of the following options' 'URL' argument.
134 option:-C 'URL', option:--control-port='URL'::
135 Listen to control data on URL 'URL' (default:
136 +tcp://{default_network_control_bind_address}:{default_network_control_port}+).
138 option:-D 'URL', option:--data-port='URL'::
139 Listen to trace data on URL 'URL' (default:
140 +tcp://{default_network_data_bind_address}:{default_network_data_port}+).
142 option:-L 'URL', option:--live-port='URL'::
143 Listen to LTTng live connections on URL 'URL'
145 +tcp://{default_network_viewer_bind_address}:{default_network_viewer_port}+).
150 option:-h, option:--help::
153 option:-V, option:--version::
157 ENVIRONMENT VARIABLES
158 ---------------------
159 `LTTNG_ABORT_ON_ERROR`::
160 Set to 1 to abort the process after the first error is encountered.
162 `LTTNG_NETWORK_SOCKET_TIMEOUT`::
163 Socket connection, receive and send timeout (milliseconds). A value
164 of 0 or -1 uses the timeout of the operating system (default).
166 `LTTNG_RELAYD_HEALTH`::
167 Path to relay daemon health's socket.
169 `LTTNG_RELAYD_TCP_KEEP_ALIVE`::
170 Set to 1 to enable TCP keep-alive.
172 The TCP keep-alive mechanism allows the detection of dead peers
173 (man:lttng-sessiond(8)) in cases of unclean termination
174 (for example, a hard reset) of a peer.
176 Supported on Linux and Solaris only. The default behaviour of the TCP
177 keep-alive mechanism is OS-specific.
179 Search for `tcp_keepalive` in man:tcp(7) for more information.
181 `LTTNG_RELAYD_TCP_KEEP_ALIVE_ABORT_THRESHOLD`::
182 The time threshold in seconds to abort a TCP connection after the keep-alive
183 probing mechanism has failed.
185 Set to 0 or -1 to use the value chosen by the operating system (default).
187 Supported on Solaris 11 only.
189 Search for `tcp_keepalive_abort_threshold` in man:tcp(7) for more information.
191 `LTTNG_RELAYD_TCP_KEEP_ALIVE_IDLE_TIME`::
192 Number of seconds a connection needs to be idle before TCP begins
193 sending out keep-alive probes.
195 Set to 0 or -1 to use the value chosen by the operating system (default).
197 Supported on Linux and Solaris 11 only.
199 On Solaris{nbsp}11, the accepted values are -1, 0, and 10 to 864000.
201 Search for `tcp_keepalive_time` and `tcp_keepalive_interval`
202 in man:tcp(7) on Solaris 11 for more information.
204 `LTTNG_RELAYD_TCP_KEEP_ALIVE_MAX_PROBE_COUNT`::
205 Maximum number of TCP keep-alive probes to send before giving up and
206 killing the connection if no response is obtained from the other end.
208 Set to 0 or -1 to use the value chosen by the operating system (default).
210 Supported on Linux only.
212 Search for `tcp_keepalive_probes` in man:tcp(7) for more information.
214 `LTTNG_RELAYD_TCP_KEEP_ALIVE_PROBE_INTERVAL`::
215 Number of seconds between TCP keep-alive probes.
217 Set to 0 or -1 to use the value chosen by the operating system (default).
219 Supported on Linux only.
221 Search for `tcp_keepalive_intvl` in man:tcp(7) for more information.
226 `$LTTNG_HOME/.lttng`::
227 User LTTng runtime and configuration directory.
229 `$LTTNG_HOME/lttng-traces`::
230 Default output directory of LTTng traces. This can be overridden
231 with the option:--output option.
233 NOTE: `$LTTNG_HOME` defaults to `$HOME` when not explicitly set.
250 As of this version, only the TCP protocol is supported for both control
251 and data ports. In future versions, TCP will remain the sole available
252 protocol for control data since those communications are low-volume and
253 need absolute reliability; trace data could be carried over UDP.
255 For an unprivileged user running `lttng-relayd`, the maximum number of
256 file descriptors per process is usually 1024. This limits the number of
257 connections and opened trace files. This limit can be configured with
261 include::common-footer.txt[]
267 man:lttng-sessiond(8),