1SYSTEMD.JOURNAL-FIELDS(7)   systemd.journal-fields   SYSTEMD.JOURNAL-FIELDS(7)
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NAME

6       systemd.journal-fields - Special journal fields
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DESCRIPTION

9       Entries in the journal resemble an environment block in their syntax
10       but with fields that can include binary data. Primarily, fields are
11       formatted UTF-8 text strings, and binary formatting is used only where
12       formatting as UTF-8 text strings makes little sense. New fields may
13       freely be defined by applications, but a few fields have special
14       meaning. All fields with special meanings are optional. In some cases,
15       fields may appear more than once per entry.
16

USER JOURNAL FIELDS

18       User fields are fields that are directly passed from clients and stored
19       in the journal.
20
21       MESSAGE=
22           The human-readable message string for this entry. This is supposed
23           to be the primary text shown to the user. It is usually not
24           translated (but might be in some cases), and is not supposed to be
25           parsed for meta data.
26
27       MESSAGE_ID=
28           A 128-bit message identifier ID for recognizing certain message
29           types, if this is desirable. This should contain a 128-bit ID
30           formatted as a lower-case hexadecimal string, without any
31           separating dashes or suchlike. This is recommended to be a
32           UUID-compatible ID, but this is not enforced, and formatted
33           differently. Developers can generate a new ID for this purpose with
34           journalctl --new-id.
35
36       PRIORITY=
37           A priority value between 0 ("emerg") and 7 ("debug") formatted as a
38           decimal string. This field is compatible with syslog's priority
39           concept.
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41       CODE_FILE=, CODE_LINE=, CODE_FUNC=
42           The code location generating this message, if known. Contains the
43           source filename, the line number and the function name.
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45       ERRNO=
46           The low-level Unix error number causing this entry, if any.
47           Contains the numeric value of errno(3) formatted as a decimal
48           string.
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50       SYSLOG_FACILITY=, SYSLOG_IDENTIFIER=, SYSLOG_PID=
51           Syslog compatibility fields containing the facility (formatted as
52           decimal string), the identifier string (i.e. "tag"), and the client
53           PID. (Note that the tag is usually derived from glibc's
54           program_invocation_short_name variable, see
55           program_invocation_short_name(3).)
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TRUSTED JOURNAL FIELDS

58       Fields prefixed with an underscore are trusted fields, i.e. fields that
59       are implicitly added by the journal and cannot be altered by client
60       code.
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62       _PID=, _UID=, _GID=
63           The process, user, and group ID of the process the journal entry
64           originates from formatted as a decimal string.
65
66       _COMM=, _EXE=, _CMDLINE=
67           The name, the executable path, and the command line of the process
68           the journal entry originates from.
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70       _CAP_EFFECTIVE=
71           The effective capabilities(7) of the process the journal entry
72           originates from.
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74       _AUDIT_SESSION=, _AUDIT_LOGINUID=
75           The session and login UID of the process the journal entry
76           originates from, as maintained by the kernel audit subsystem.
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78       _SYSTEMD_CGROUP=, _SYSTEMD_SESSION=, _SYSTEMD_UNIT=,
79       _SYSTEMD_USER_UNIT=, _SYSTEMD_OWNER_UID=, _SYSTEMD_SLICE=
80           The control group path in the systemd hierarchy, the systemd
81           session ID (if any), the systemd unit name (if any), the systemd
82           user session unit name (if any), the owner UID of the systemd
83           session (if any) and the systemd slice unit of the process the
84           journal entry originates from.
85
86       _SELINUX_CONTEXT=
87           The SELinux security context (label) of the process the journal
88           entry originates from.
89
90       _SOURCE_REALTIME_TIMESTAMP=
91           The earliest trusted timestamp of the message, if any is known that
92           is different from the reception time of the journal. This is the
93           time in microseconds since the epoch UTC, formatted as a decimal
94           string.
95
96       _BOOT_ID=
97           The kernel boot ID for the boot the message was generated in,
98           formatted as a 128-bit hexadecimal string.
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100       _MACHINE_ID=
101           The machine ID of the originating host, as available in machine-
102           id(5).
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104       _HOSTNAME=
105           The name of the originating host.
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107       _TRANSPORT=
108           How the entry was received by the journal service. Valid transports
109           are:
110
111           driver
112               for internally generated messages
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114           syslog
115               for those received via the local syslog socket with the syslog
116               protocol
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118           journal
119               for those received via the native journal protocol
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121           stdout
122               for those read from a service's standard output or error output
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124           kernel
125               for those read from the kernel
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127       _STREAM_ID=
128           Only applies to "_TRANSPORT=stream" records: specifies a randomized
129           128bit ID assigned to the stream connection when it was first
130           created. This ID is useful to reconstruct individual log streams
131           from the log records: all log records carrying the same stream ID
132           originate from the same stream.
133
134       _LINE_BREAK=
135           Only applies to "_TRANSPORT=stream" records: indicates that the log
136           message in the standard output/error stream was not terminated with
137           a normal newline character ("\n", i.e. ASCII 10). Specifically,
138           when set this field is one of nul (in case the line was terminated
139           by a NUL byte), line-max (in case the maximum log line length was
140           reached, as configured with LineMax= in journald.conf(5)) or eof
141           (if this was the last log record of a stream and the stream ended
142           without a final newline character). Note that this record is not
143           generated when a normal newline character was used for marking the
144           log line end.
145

KERNEL JOURNAL FIELDS

147       Kernel fields are fields that are used by messages originating in the
148       kernel and stored in the journal.
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150       _KERNEL_DEVICE=
151           The kernel device name. If the entry is associated to a block
152           device, the major and minor of the device node, separated by ":"
153           and prefixed by "b". Similar for character devices but prefixed by
154           "c". For network devices, this is the interface index prefixed by
155           "n". For all other devices, this is the subsystem name prefixed by
156           "+", followed by ":", followed by the kernel device name.
157
158       _KERNEL_SUBSYSTEM=
159           The kernel subsystem name.
160
161       _UDEV_SYSNAME=
162           The kernel device name as it shows up in the device tree below
163           /sys.
164
165       _UDEV_DEVNODE=
166           The device node path of this device in /dev.
167
168       _UDEV_DEVLINK=
169           Additional symlink names pointing to the device node in /dev. This
170           field is frequently set more than once per entry.
171

FIELDS TO LOG ON BEHALF OF A DIFFERENT PROGRAM

173       Fields in this section are used by programs to specify that they are
174       logging on behalf of another program or unit.
175
176       Fields used by the systemd-coredump coredump kernel helper:
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178       COREDUMP_UNIT=, COREDUMP_USER_UNIT=
179           Used to annotate messages containing coredumps from system and
180           session units. See coredumpctl(1).
181
182       Priviledged programs (currently UID 0) may attach OBJECT_PID= to a
183       message. This will instruct systemd-journald to attach additional
184       fields on behalf of the caller:
185
186       OBJECT_PID=PID
187           PID of the program that this message pertains to.
188
189       OBJECT_UID=, OBJECT_GID=, OBJECT_COMM=, OBJECT_EXE=, OBJECT_CMDLINE=,
190       OBJECT_AUDIT_SESSION=, OBJECT_AUDIT_LOGINUID=, OBJECT_SYSTEMD_CGROUP=,
191       OBJECT_SYSTEMD_SESSION=, OBJECT_SYSTEMD_OWNER_UID=,
192       OBJECT_SYSTEMD_UNIT=, OBJECT_SYSTEMD_USER_UNIT=
193           These are additional fields added automatically by
194           systemd-journald. Their meaning is the same as _UID=, _GID=,
195           _COMM=, _EXE=, _CMDLINE=, _AUDIT_SESSION=, _AUDIT_LOGINUID=,
196           _SYSTEMD_CGROUP=, _SYSTEMD_SESSION=, _SYSTEMD_UNIT=,
197           _SYSTEMD_USER_UNIT=, and _SYSTEMD_OWNER_UID= as described above,
198           except that the process identified by PID is described, instead of
199           the process which logged the message.
200

ADDRESS FIELDS

202       During serialization into external formats, such as the Journal Export
203       Format[1] or the Journal JSON Format[2], the addresses of journal
204       entries are serialized into fields prefixed with double underscores.
205       Note that these are not proper fields when stored in the journal but
206       for addressing metadata of entries. They cannot be written as part of
207       structured log entries via calls such as sd_journal_send(3). They may
208       also not be used as matches for sd_journal_add_match(3)
209
210       __CURSOR=
211           The cursor for the entry. A cursor is an opaque text string that
212           uniquely describes the position of an entry in the journal and is
213           portable across machines, platforms and journal files.
214
215       __REALTIME_TIMESTAMP=
216           The wallclock time (CLOCK_REALTIME) at the point in time the entry
217           was received by the journal, in microseconds since the epoch UTC,
218           formatted as a decimal string. This has different properties from
219           "_SOURCE_REALTIME_TIMESTAMP=", as it is usually a bit later but
220           more likely to be monotonic.
221
222       __MONOTONIC_TIMESTAMP=
223           The monotonic time (CLOCK_MONOTONIC) at the point in time the entry
224           was received by the journal in microseconds, formatted as a decimal
225           string. To be useful as an address for the entry, this should be
226           combined with the boot ID in "_BOOT_ID=".
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SEE ALSO

229       systemd(1), journalctl(1), journald.conf(5), sd-journal(3),
230       coredumpctl(1), systemd.directives(7)
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NOTES

233        1. Journal Export Format
234           http://www.freedesktop.org/wiki/Software/systemd/export
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236        2. Journal JSON Format
237           http://www.freedesktop.org/wiki/Software/systemd/json
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241systemd 219                                          SYSTEMD.JOURNAL-FIELDS(7)
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