lttng-untrack(1)
================
:revdate: 14 June 2021


NAME
----
lttng-untrack - Disallow specific processes to record LTTng events


SYNOPSIS
--------
Disallow specific processes to record Linux kernel events:

[verse]
*lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *untrack* option:--kernel [option:--session='SESSION']
      (option:--pid=PID[,PID]... | option:--vpid=VPID[,VPID]... |
       option:--uid=UID[,UID]... | option:--vuid=VUSER[,VUSER]... |
       option:--gid=GID[,GID]... | option:--vgid=VGROUP[,VGROUP]...)...

[verse]
*lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *untrack* option:--kernel [option:--session='SESSION']
      option:--all (option:--pid | option:--vpid | option:--uid | option:--vuid | option:--gid | option:--vgid)...

Disallow specific processes to record user space events:

[verse]
*lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *untrack* option:--userspace [option:--session='SESSION']
      (option:--vpid=VPID[,VPID]... | option:--vuid=VUSER[,VUSER]... |
       option:--vgid=VGROUP[,VGROUP]...)...

[verse]
*lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *untrack* option:--userspace [option:--session='SESSION']
      option:--all (option:--vpid | option:--vgid | option:--vuid)...


DESCRIPTION
-----------
The `lttng untrack` command disallows one or more processes to record
LTTng events based on their attributes within:

With the option:--session='SESSION' option::
    The recording session named 'SESSION'.

Without the option:--session option::
    The current recording session (see man:lttng-concepts(7) to learn
    more about the current recording session).

See man:lttng-concepts(7) to learn more about recording sessions and
recording event rules.

The `untrack` command removes values from _inclusion sets_ of process
attributes. See man:lttng-track(1) to learn more about inclusion sets.

See the ``<<examples,EXAMPLES>>'' section below for usage examples.


Inclusion set example
~~~~~~~~~~~~~~~~~~~~~
A common operation is to create a recording session (see
man:lttng-create(1)), remove all the entries from the Linux kernel
process ID inclusion set, start recording, and then manually add PIDs
while the recording session is active.

Assume the maximum system PID is 7 for this example.

. Command:
+
[role="term"]
----
$ lttng create
----
+
Initial inclusion set:
+
-------------------------------
[0] [1] [2] [3] [4] [5] [6] [7]
-------------------------------

. Command:
+
[role="term"]
----
$ lttng untrack --kernel --all --pid
----
+
Inclusion set:
+
-------------------------------
[ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ]
-------------------------------

. Commands:
+
[role="term"]
----
$ lttng enable-event --kernel ...
$ lttng start
$ # ...
$ lttng track --kernel --pid=3,5
----
+
Inclusion set:
+
-------------------------------
[ ] [ ] [ ] [3] [ ] [5] [ ] [ ]
-------------------------------

. Command:
+
[role="term"]
----
$ lttng track --kernel --pid=2
----
+
Inclusion set:
+
-------------------------------
[ ] [ ] [2] [3] [ ] [5] [ ] [ ]
-------------------------------


include::common-lttng-cmd-options-head.txt[]


Tracing domain
~~~~~~~~~~~~~~
One of:

option:-k, option:--kernel::
    Remove values from one or more Linux kernel inclusion sets.

option:-u, option:--userspace::
    Remove values from one or more user space inclusion sets.


Recording target
~~~~~~~~~~~~~~~~
option:-s 'SESSION', option:--session='SESSION'::
    Remove values from one or more inclusion sets of the recording
    session named 'SESSION' instead of the current recording session.


Inclusion set selection
~~~~~~~~~~~~~~~~~~~~~~~
option:-p ['PID'[,'PID']...], option:--pid[='PID'[,'PID']...]::
    For each 'PID' argument, remove 'PID' from the process ID inclusion
    set of the selected recording session and domain.
+
'PID' is the process ID attribute of a process as seen from the root
PID namespace (see man:pid_namespaces(7)).
+
Only available with option:--kernel option.

option:--vpid[='VPID'[,'VPID']...]::
    For each 'VPID' argument, remove 'VPID' from the virtual process ID
    inclusion set of the selected recording session and domain.
+
'VPID' is the virtual process ID attribute of a process as seen from
the PID namespace of the process (see man:pid_namespaces(7)).

option:--uid[='USER'[,'USER']...]::
    For each 'USER' argument, remove 'USER' from the user ID inclusion
    set of the selected recording session and domain.
+
'USER' is either:
+
--
* The real user ID (see man:getuid(3)) of a process as seen
  from the root user namespace (see man:user_namespaces(7)).

* A user name.
+
The connected LTTng session daemon (see man:lttng-sessiond(8)) performs
the user name resolution on removal from the user ID inclusion set.
--
+
Only available with option:--kernel option.

option:--vuid[='VUSER'[,'VUSER']...]::
    For each 'VUSER' argument, remove 'VUSER' from the virtual user ID
    inclusion set of the selected recording session and domain.
+
'VUSER' is either:
+
--
* The real user ID (see man:getuid(3)) of a process as seen
  from the user namespace (see man:user_namespaces(7)).

* A user name.
+
The connected LTTng session daemon (see man:lttng-sessiond(8)) performs
the user name resolution on removal from the virtual user ID inclusion
set.
--

option:--gid[='GROUP'[,'GROUP']...]::
    For each 'GROUP' argument, remove 'GROUP' from the group ID
    inclusion set of the selected recording session and domain.
+
'GROUP' is either:
+
--
* The real group ID (see man:getgid(3)) of a process as seen from the
  root user namespace (see man:user_namespaces(7)).

* A group name.
+
The connected LTTng session daemon (see man:lttng-sessiond(8)) performs
the group name resolution on removal from the group ID inclusion set.
--
+
Only available with option:--kernel option.

option:--vgid[='VGROUP'[,'VGROUP']...]::
    For each 'VGROUP' argument, remove 'VGROUP' from the virtual group
    ID inclusion set of the selected recording session and domain.
+
'VGROUP' is either:
+
--
* The real group ID (see man:getgid(3)) of a process as seen
  from the user namespace (see man:user_namespaces(7)).

* A group name.
+
The connected LTTng session daemon (see man:lttng-sessiond(8)) performs
the group name resolution on removal from the virtual group ID inclusion
set.
--


Inclusion set operation
~~~~~~~~~~~~~~~~~~~~~~~
option:-a, option:--all::
    With one or more empty option:--pid, option:--vpid, option:--uid,
    option:--vuid, option:--gid, and option:--vgid options: clear the
    selected inclusion sets.


include::common-lttng-cmd-help-options.txt[]


include::common-lttng-cmd-after-options.txt[]


[[examples]]
EXAMPLES
--------
.Remove the PIDs 1728 and 3775 from the Linux kernel process ID inclusion set of the current recording session.
====
See the option:--pid option.

[role="term"]
----
$ lttng untrack --kernel --pid=1728,3775
----
====

.Remove the IDs of a specific groups from the user space virtual group ID inclusion set of a specific recording session.
====
See the option:--vgid and option:--session options.

[role="term"]
----
$ lttng untrack --userspace --session=my-session \
                --vgid=docker,mysql
----
====

.Remove all the user IDs from the Linux kernel user ID inclusion set of the current recording session.
====
See the option:--all and option:--uid options.

[role="term"]
----
$ lttng untrack --kernel --all --uid
----
====


include::common-footer.txt[]


SEE ALSO
--------
man:lttng(1),
man:lttng-track(1),
man:lttng-concepts(7)