--- /dev/null
+lttng-create(1)
+===============
+
+
+NAME
+----
+lttng-create - Create an LTTng tracing session
+
+
+SYNOPSIS
+--------
+Normal mode:
+
+[verse]
+*lttng* ['GENERAL OPTIONS'] *create* [option:--output='PATH' | option:--no-output]
+ [option:--shm-path='PATH'] ['SESSION']
+
+Snapshot mode:
+
+[verse]
+*lttng* ['GENERAL OPTIONS'] *create* option:--snapshot
+ [option:--set-url='URL' | option:--ctrl-url='URL' option:--data-url='URL']
+ [option:--shm-path='PATH'] ['SESSION']
+
+Live mode:
+
+[verse]
+*lttng* ['GENERAL OPTIONS'] *create* option:--live[='DELAYUS']
+ [option:--set-url='URL' | option:--ctrl-url='URL' option:--data-url='URL']
+ [option:--shm-path='PATH'] ['SESSION']
+
+
+DESCRIPTION
+-----------
+The `lttng create` command creates a new tracing session.
+
+A tracing session is a named container of channels, which in turn
+contain event rules. It is domain-agnostic, in that channels and event
+rules can be enabled for the user space tracer and/or the Linux
+kernel tracer.
+
+On execution, an `.lttngrc` file is created, if it does not exist, in the
+user's home directory. This file contains the name of the current tracing
+session. When creating a new tracing session with `lttng create`, the
+current tracing session is set to this new tracing session. The
+linklttng:lttng-set-session(1) command can be used to set the current
+tracing session without manually editing the `.lttngrc` file.
+
+If 'SESSION' is omitted, a session name is automatically created having
+this form: `auto-YYYYmmdd-HHMMSS`. 'SESSION' *must not* contain the
+character `/`.
+
+The option:--shm-path option can be used to specify the path to the
+shared memory holding the ring buffers. Specifying a location on an
+NVRAM file system makes it possible to retrieve the latest recorded
+trace data when the system reboots after a crash. To view the events
+of ring buffer files after a system crash, use the
+linklttng:lttng-crash(1) utility.
+
+Tracing sessions are destroyed using the linklttng:lttng-destroy(1)
+command.
+
+
+Creation modes
+~~~~~~~~~~~~~~
+There are three tracing session modes:
+
+Normal mode::
+ Traces the local system and writes the trace to the local
+ file system. The option:--output option specifies the trace path.
+ If omitted, the trace is written in the `$LTTNG_HOME/lttng-traces`
+ directory (`$LTTNG_HOME` defaults to `$HOME`). The file system
+ output can be disabled using the option:--no-output option.
+
+Snapshot mode::
+ Traces the local system without writing the trace to the local file
+ system (implicit option:--no-output option). Channels are automatically
+ configured to be snapshot-ready on creation (see
+ linklttng:lttng-enable-channel(1)). The linklttng:lttng-snapshot(1)
+ command is used to take snapshots of the current ring buffers.
+ The option:--set-url, or option:--ctrl-url and option:--data-url
+ options set the default snapshot output destination.
+
+Live mode::
+ Traces the local system, sending trace data to an LTTng relay daemon
+ over the network (see linklttng:lttng-relayd(8)). The
+ option:--set-url, or option:--ctrl-url and option:--data-url options
+ set the trace output destination. The live output URLs cannot use
+ the `file://` protocol (see URL format below).
+
+
+[[url-format]]
+URL format
+~~~~~~~~~~
+The option:--set-url, option:--ctrl-url, and option:--data-url options
+specify URLs.
+
+The format of those URLs is one of:
+
+[verse]
+file://'TRACEPATH'
+'NETPROTO'://('HOST' | 'IPADDR')[:__CTRLPORT__[:__DATAPORT__]][/'TRACEPATH']
+
+The `file://` protocol targets the *local file system*.
+
+'TRACEPATH'::
+ Absolute path to trace files on the local file system.
+
+The other version is used for *network streaming*.
+
+'NETPROTO'::
+ Network protocol, amongst:
++
+* `net`: TCP over IPv4; the default values of `<ctrl port>` and
+ `<data port>` are resp. 5342 and 5343
+* `net6`: TCP over IPv6: same default ports as `net` protocol
+* `tcp`: same as `net` protocol; can only be used with the
+ option:--ctrl-url and option:--data-url options together
+* `tcp6`: same as `net6` protocol; can only be used with the
+ option:--ctrl-url and option:--data-url options together
+
+('HOST' | 'IPADDR')::
+ Hostname or IP address (IPv6 address *must* be enclosed in brackets
+ (`[` and `]`); see https://www.ietf.org/rfc/rfc2732.txt[RFC 2732]).
+
+'CTRLPORT'::
+ Control port.
+
+'DATAPORT'::
+ Data port.
+
+'TRACEPATH'::
+ Path of trace files on the remote file system. This path is relative
+ to the base output directory set on the relay daemon side;
+ see linklttng:lttng-relayd(8).
+
+
+include::common-cmd-options-head.txt[]
+
+
+Mode
+~~~~
+option:--live[='DELAYUS']::
+ Create the session in live mode. The optional 'DELAYUS' parameter,
+ given in microseconds, is the maximum time the user can wait for
+ the data to be flushed. This mode can be set with a network URL
+ (options option:--set-url, or option:--ctrl-url and option:--data-url)
+ and must have a relay daemon listening (see linklttng:lttng-relayd(1)).
++
+By default, 'DELAYUS' is 1000000 and the network URL is set to
+`net://127.0.0.1`.
+
+option:--snapshot::
+ Create the session in snapshot mode. This is the equivalent of using
+ the option:--no-output option and creating all the channels of this
+ new tracing session in overwrite mode with an `mmap` output type.
+
+
+Output
+~~~~~~
+option:--no-output::
+ Do not output any trace data.
+
+option:-o, option:--output='PATH'::
+ Set trace output path to 'PATH'.
+
+option:--shm-path='PATH'::
+ Create shared memory holding buffers at 'PATH'.
+
+
+URL
+~~~
+See the <<url-format,URL format>> section above for more information
+about the syntax of the following options' 'URL' argument.
+
+option:-C, option:--ctrl-url='URL'::
+ Set control path URL to 'URL' (must use option:--data-url option
+ also).
+
+option:-D, option:--data-url='URL'::
+ Set data path URL to 'URL' (must use option:--ctrl-url option
+ also).
+
+option:-U, option:--set-url='URL'::
+ Set URL destination of the trace data to 'URL'. It is persistent for
+ the session lifetime. This option sets both data
+ (option:--data-url option) and control (option:--ctrl-url option)
+ URLs at the same time.
+
+
+include::common-cmd-help-options.txt[]
+
+
+include::common-cmd-footer.txt[]
+
+
+SEE ALSO
+--------
+linklttng:lttng-destroy(1),
+linklttng:lttng-set-session(1),
+linklttng:lttng(1)
projects / lttng-tools.git / commitdiff
