1JOURNALD.CONF(5) journald.conf JOURNALD.CONF(5)
2
6 journald.conf, journald.conf.d, journald@.conf - Journal service
7 configuration files
8
10 /etc/systemd/journald.conf
11 /etc/systemd/journald.conf.d/*.conf
13 /run/systemd/journald.conf.d/*.conf
15 /usr/lib/systemd/journald.conf.d/*.conf
17 /etc/systemd/journald@NAMESPACE.conf
19
21 These files configure various parameters of the systemd journal
22 service, systemd-journald.service(8). See systemd.syntax(5) for a
23 general description of the syntax.
24 The systemd-journald instance managing the default namespace is
26 configured by /etc/systemd/journald.conf and associated drop-ins.
27 Instances managing other namespaces read
28 /etc/systemd/journald@NAMESPACE.conf with the namespace identifier
29 filled in. This allows each namespace to carry a distinct
30 configuration. See systemd-journald.service(8) for details about
31 journal namespaces.
32
34 The default configuration is defined during compilation, so a
35 configuration file is only needed when it is necessary to deviate from
36 those defaults. By default, the configuration file in /etc/systemd/
37 contains commented out entries showing the defaults as a guide to the
38 administrator. This file can be edited to create local overrides.
39 When packages need to customize the configuration, they can install
41 configuration snippets in /usr/lib/systemd/*.conf.d/ or
42 /usr/local/lib/systemd/*.conf.d/. The main configuration file is read
43 before any of the configuration directories, and has the lowest
44 precedence; entries in a file in any configuration directory override
45 entries in the single configuration file. Files in the *.conf.d/
46 configuration subdirectories are sorted by their filename in
47 lexicographic order, regardless of in which of the subdirectories they
48 reside. When multiple files specify the same option, for options which
49 accept just a single value, the entry in the file with the
50 lexicographically latest name takes precedence. For options which
51 accept a list of values, entries are collected as they occur in files
52 sorted lexicographically.
53 Files in /etc/ are reserved for the local administrator, who may use
55 this logic to override the configuration files installed by vendor
56 packages. It is recommended to prefix all filenames in those
57 subdirectories with a two-digit number and a dash, to simplify the
58 ordering of the files.
59 To disable a configuration file supplied by the vendor, the recommended
61 way is to place a symlink to /dev/null in the configuration directory
62 in /etc/, with the same filename as the vendor configuration file.
63
65 All options are configured in the "[Journal]" section:
66 Storage=
68 Controls where to store journal data. One of "volatile",
69 "persistent", "auto" and "none". If "volatile", journal log data
70 will be stored only in memory, i.e. below the /run/log/journal
71 hierarchy (which is created if needed). If "persistent", data will
72 be stored preferably on disk, i.e. below the /var/log/journal
73 hierarchy (which is created if needed), with a fallback to
74 /run/log/journal (which is created if needed), during early boot
75 and if the disk is not writable. "auto" is similar to "persistent"
76 but the directory /var/log/journal is not created if needed, so
77 that its existence controls where log data goes. "none" turns off
78 all storage, all log data received will be dropped. Forwarding to
79 other targets, such as the console, the kernel log buffer, or a
80 syslog socket will still work however. Defaults to "auto" in the
81 default journal namespace, and "persistent" in all others.
82 Compress=
84 Can take a boolean value. If enabled (the default), data objects
85 that shall be stored in the journal and are larger than the default
86 threshold of 512 bytes are compressed before they are written to
87 the file system. It can also be set to a number of bytes to specify
88 the compression threshold directly. Suffixes like K, M, and G can
89 be used to specify larger units.
90 Seal=
92 Takes a boolean value. If enabled (the default), and a sealing key
93 is available (as created by journalctl(1)'s --setup-keys command),
94 Forward Secure Sealing (FSS) for all persistent journal files is
95 enabled. FSS is based on Seekable Sequential Key Generators[1] by
96 G. A. Marson and B. Poettering (doi:10.1007/978-3-642-40203-6_7)
97 and may be used to protect journal files from unnoticed alteration.
98 SplitMode=
100 Controls whether to split up journal files per user, either "uid"
101 or "none". Split journal files are primarily useful for access
102 control: on UNIX/Linux access control is managed per file, and the
103 journal daemon will assign users read access to their journal
104 files. If "uid", all regular users (with UID outside the range of
105 system users, dynamic service users, and the nobody user) will each
106 get their own journal files, and system users will log to the
107 system journal. See Users, Groups, UIDs and GIDs on systemd
108 systems[2] for more details about UID ranges. If "none", journal
109 files are not split up by user and all messages are instead stored
110 in the single system journal. In this mode unprivileged users
111 generally do not have access to their own log data. Note that
112 splitting up journal files by user is only available for journals
113 stored persistently. If journals are stored on volatile storage
114 (see Storage= above), only a single journal file is used. Defaults
115 to "uid".
116 RateLimitIntervalSec=, RateLimitBurst=
118 Configures the rate limiting that is applied to all messages
119 generated on the system. If, in the time interval defined by
120 RateLimitIntervalSec=, more messages than specified in
121 RateLimitBurst= are logged by a service, all further messages
122 within the interval are dropped until the interval is over. A
123 message about the number of dropped messages is generated. This
124 rate limiting is applied per-service, so that two services which
125 log do not interfere with each other's limits. Defaults to 10000
126 messages in 30s. The time specification for RateLimitIntervalSec=
127 may be specified in the following units: "s", "min", "h", "ms",
128 "us". To turn off any kind of rate limiting, set either value to 0.
129 Note that the effective rate limit is multiplied with a factor
131 derived from the available free disk space for the journal.
132 Currently, this factor is calculated using the base 2 logarithm.
133 Table 1. Example RateLimitBurst= rate modifications by the
135 available disk space
136 ┌─────────────────────┬──────────────────┐
137 │Available Disk Space │ Burst Multiplier │
138 ├─────────────────────┼──────────────────┤
139 │<= 1MB │ 1 │
140 ├─────────────────────┼──────────────────┤
141 │<= 16MB │ 2 │
142 ├─────────────────────┼──────────────────┤
143 │<= 256MB │ 3 │
144 ├─────────────────────┼──────────────────┤
145 │<= 4GB │ 4 │
146 ├─────────────────────┼──────────────────┤
147 │<= 64GB │ 5 │
148 ├─────────────────────┼──────────────────┤
149 │<= 1TB │ 6 │
150 └─────────────────────┴──────────────────┘
151 If a service provides rate limits for itself through
152 LogRateLimitIntervalSec= and/or LogRateLimitBurst= in
153 systemd.exec(5), those values will override the settings specified
154 here.
155 SystemMaxUse=, SystemKeepFree=, SystemMaxFileSize=, SystemMaxFiles=,
157 RuntimeMaxUse=, RuntimeKeepFree=, RuntimeMaxFileSize=, RuntimeMaxFiles=
158 Enforce size limits on the journal files stored. The options
159 prefixed with "System" apply to the journal files when stored on a
160 persistent file system, more specifically /var/log/journal. The
161 options prefixed with "Runtime" apply to the journal files when
162 stored on a volatile in-memory file system, more specifically
163 /run/log/journal. The former is used only when /var is mounted,
164 writable, and the directory /var/log/journal exists. Otherwise,
165 only the latter applies. Note that this means that during early
166 boot and if the administrator disabled persistent logging, only the
167 latter options apply, while the former apply if persistent logging
168 is enabled and the system is fully booted up. journalctl and
169 systemd-journald ignore all files with names not ending with
170 ".journal" or ".journal~", so only such files, located in the
171 appropriate directories, are taken into account when calculating
172 current disk usage.
173 SystemMaxUse= and RuntimeMaxUse= control how much disk space the
175 journal may use up at most. SystemKeepFree= and RuntimeKeepFree=
176 control how much disk space systemd-journald shall leave free for
177 other uses. systemd-journald will respect both limits and use the
178 smaller of the two values.
179 The first pair defaults to 10% and the second to 15% of the size of
181 the respective file system, but each value is capped to 4G. If the
182 file system is nearly full and either SystemKeepFree= or
183 RuntimeKeepFree= are violated when systemd-journald is started, the
184 limit will be raised to the percentage that is actually free. This
185 means that if there was enough free space before and journal files
186 were created, and subsequently something else causes the file
187 system to fill up, journald will stop using more space, but it will
188 not be removing existing files to reduce the footprint again,
189 either. Also note that only archived files are deleted to reduce
190 the space occupied by journal files. This means that, in effect,
191 there might still be more space used than SystemMaxUse= or
192 RuntimeMaxUse= limit after a vacuuming operation is complete.
193 SystemMaxFileSize= and RuntimeMaxFileSize= control how large
195 individual journal files may grow at most. This influences the
196 granularity in which disk space is made available through rotation,
197 i.e. deletion of historic data. Defaults to one eighth of the
198 values configured with SystemMaxUse= and RuntimeMaxUse=, so that
199 usually seven rotated journal files are kept as history.
200 Specify values in bytes or use K, M, G, T, P, E as units for the
202 specified sizes (equal to 1024, 1024², ... bytes). Note that size
203 limits are enforced synchronously when journal files are extended,
204 and no explicit rotation step triggered by time is needed.
205 SystemMaxFiles= and RuntimeMaxFiles= control how many individual
207 journal files to keep at most. Note that only archived files are
208 deleted to reduce the number of files until this limit is reached;
209 active files will stay around. This means that, in effect, there
210 might still be more journal files around in total than this limit
211 after a vacuuming operation is complete. This setting defaults to
212 100.
213 MaxFileSec=
215 The maximum time to store entries in a single journal file before
216 rotating to the next one. Normally, time-based rotation should not
217 be required as size-based rotation with options such as
218 SystemMaxFileSize= should be sufficient to ensure that journal
219 files do not grow without bounds. However, to ensure that not too
220 much data is lost at once when old journal files are deleted, it
221 might make sense to change this value from the default of one
222 month. Set to 0 to turn off this feature. This setting takes time
223 values which may be suffixed with the units "year", "month",
224 "week", "day", "h" or "m" to override the default time unit of
225 seconds.
226 MaxRetentionSec=
228 The maximum time to store journal entries. This controls whether
229 journal files containing entries older than the specified time span
230 are deleted. Normally, time-based deletion of old journal files
231 should not be required as size-based deletion with options such as
232 SystemMaxUse= should be sufficient to ensure that journal files do
233 not grow without bounds. However, to enforce data retention
234 policies, it might make sense to change this value from the default
235 of 0 (which turns off this feature). This setting also takes time
236 values which may be suffixed with the units "year", "month",
237 "week", "day", "h" or " m" to override the default time unit of
238 seconds.
239 SyncIntervalSec=
241 The timeout before synchronizing journal files to disk. After
242 syncing, journal files are placed in the OFFLINE state. Note that
243 syncing is unconditionally done immediately after a log message of
244 priority CRIT, ALERT or EMERG has been logged. This setting hence
245 applies only to messages of the levels ERR, WARNING, NOTICE, INFO,
246 DEBUG. The default timeout is 5 minutes.
247 ForwardToSyslog=, ForwardToKMsg=, ForwardToConsole=, ForwardToWall=
249 Control whether log messages received by the journal daemon shall
250 be forwarded to a traditional syslog daemon, to the kernel log
251 buffer (kmsg), to the system console, or sent as wall messages to
252 all logged-in users. These options take boolean arguments. If
253 forwarding to syslog is enabled but nothing reads messages from the
254 socket, forwarding to syslog has no effect. By default, only
255 forwarding to wall is enabled. These settings may be overridden at
256 boot time with the kernel command line options
257 "systemd.journald.forward_to_syslog",
258 "systemd.journald.forward_to_kmsg",
259 "systemd.journald.forward_to_console", and
260 "systemd.journald.forward_to_wall". If the option name is specified
261 without "=" and the following argument, true is assumed. Otherwise,
262 the argument is parsed as a boolean.
263 When forwarding to the console, the TTY to log to can be changed
265 with TTYPath=, described below.
266 When forwarding to the kernel log buffer (kmsg), make sure to
268 select a suitably large size for the log buffer, for example by
269 adding "log_buf_len=8M" to the kernel command line. systemd will
270 automatically disable kernel's rate-limiting applied to userspace
271 processes (equivalent to setting "printk.devkmsg=on").
272 MaxLevelStore=, MaxLevelSyslog=, MaxLevelKMsg=, MaxLevelConsole=,
274 MaxLevelWall=
275 Controls the maximum log level of messages that are stored in the
276 journal, forwarded to syslog, kmsg, the console or wall (if that is
277 enabled, see above). As argument, takes one of "emerg", "alert",
278 "crit", "err", "warning", "notice", "info", "debug", or integer
279 values in the range of 0–7 (corresponding to the same levels).
280 Messages equal or below the log level specified are
281 stored/forwarded, messages above are dropped. Defaults to "debug"
282 for MaxLevelStore= and MaxLevelSyslog=, to ensure that the all
283 messages are stored in the journal and forwarded to syslog.
284 Defaults to "notice" for MaxLevelKMsg=, "info" for
285 MaxLevelConsole=, and "emerg" for MaxLevelWall=. These settings may
286 be overridden at boot time with the kernel command line options
287 "systemd.journald.max_level_store=",
288 "systemd.journald.max_level_syslog=",
289 "systemd.journald.max_level_kmsg=",
290 "systemd.journald.max_level_console=",
291 "systemd.journald.max_level_wall=".
292 ReadKMsg=
294 Takes a boolean value. If enabled systemd-journal processes
295 /dev/kmsg messages generated by the kernel. In the default journal
296 namespace this option is enabled by default, it is disabled in all
297 others.
298 TTYPath=
300 Change the console TTY to use if ForwardToConsole=yes is used.
301 Defaults to /dev/console.
302 LineMax=
304 The maximum line length to permit when converting stream logs into
305 record logs. When a systemd unit's standard output/error are
306 connected to the journal via a stream socket, the data read is
307 split into individual log records at newline ("\n", ASCII 10) and
308 NUL characters. If no such delimiter is read for the specified
309 number of bytes a hard log record boundary is artificially
310 inserted, breaking up overly long lines into multiple log records.
311 Selecting overly large values increases the possible memory usage
312 of the Journal daemon for each stream client, as in the worst case
313 the journal daemon needs to buffer the specified number of bytes in
314 memory before it can flush a new log record to disk. Also note that
315 permitting overly large line maximum line lengths affects
316 compatibility with traditional log protocols as log records might
317 not fit anymore into a single AF_UNIX or AF_INET datagram. Takes a
318 size in bytes. If the value is suffixed with K, M, G or T, the
319 specified size is parsed as Kilobytes, Megabytes, Gigabytes, or
320 Terabytes (with the base 1024), respectively. Defaults to 48K,
321 which is relatively large but still small enough so that log
322 records likely fit into network datagrams along with extra room for
323 metadata. Note that values below 79 are not accepted and will be
324 bumped to 79.
325
327 Journal events can be transferred to a different logging daemon in two
328 different ways. With the first method, messages are immediately
329 forwarded to a socket (/run/systemd/journal/syslog), where the
330 traditional syslog daemon can read them. This method is controlled by
331 the ForwardToSyslog= option. With a second method, a syslog daemon
332 behaves like a normal journal client, and reads messages from the
333 journal files, similarly to journalctl(1). With this, messages do not
334 have to be read immediately, which allows a logging daemon which is
335 only started late in boot to access all messages since the start of the
336 system. In addition, full structured meta-data is available to it. This
337 method of course is available only if the messages are stored in a
338 journal file at all. So it will not work if Storage=none is set. It
339 should be noted that usually the second method is used by syslog
340 daemons, so the Storage= option, and not the ForwardToSyslog= option,
341 is relevant for them.
342
344 systemd(1), systemd-journald.service(8), journalctl(1),
345 systemd.journal-fields(7), systemd-system.conf(5)
346
348 1. Seekable Sequential Key Generators
349 https://eprint.iacr.org/2013/397
350 2. Users, Groups, UIDs and GIDs on systemd systems
352 https://systemd.io/UIDS-GIDS
353systemd 245 JOURNALD.CONF(5)