NAME
journald.conf, journald.conf.d, [email protected] - Journal service configuration filesSYNOPSIS
/etc/systemd/journald.conf /etc/systemd/journald.conf.d/*.conf /run/systemd/journald.conf.d/*.conf /usr/lib/systemd/journald.conf.d/*.conf /etc/systemd/journald@ NAMESPACE.conf /etc/systemd/journald@ NAMESPACE.conf.d/*.conf /run/systemd/journald@ NAMESPACE.conf.d/*.conf /usr/lib/systemd/journald@ NAMESPACE.conf.d/*.confDESCRIPTION
These files configure various parameters of the systemd journal service, systemd-journald.service(8). See systemd.syntax(7) for a general description of the syntax. The systemd-journald instance managing the default namespace is configured by /etc/systemd/journald.conf and associated drop-ins. Instances managing other namespaces read /etc/systemd/journald@ NAMESPACE.conf and associated drop-ins with the namespace identifier filled in. This allows each namespace to carry a distinct configuration. See systemd-journald.service(8) for details about journal namespaces.CONFIGURATION DIRECTORIES AND PRECEDENCE
The default configuration is set during compilation, so configuration is only needed when it is necessary to deviate from those defaults. Initially, the main configuration file in /etc/systemd/ contains commented out entries showing the defaults as a guide to the administrator. Local overrides can be created by editing this file or by creating drop-ins, as described below. Using drop-ins for local configuration is recommended over modifications to the main configuration file. In addition to the "main" configuration file, drop-in configuration snippets are read from /usr/lib/systemd/*.conf.d/, /usr/local/lib/systemd/*.conf.d/, and /etc/systemd/*.conf.d/. Those drop-ins have higher precedence and override the main configuration file. Files in the *.conf.d/ configuration subdirectories are sorted by their filename in lexicographic order, regardless of in which of the subdirectories they reside. When multiple files specify the same option, for options which accept just a single value, the entry in the file sorted last takes precedence, and for options which accept a list of values, entries are collected as they occur in the sorted files. When packages need to customize the configuration, they can install drop-ins under /usr/. Files in /etc/ are reserved for the local administrator, who may use this logic to override the configuration files installed by vendor packages. Drop-ins have to be used to override package drop-ins, since the main configuration file has lower precedence. It is recommended to prefix all filenames in those subdirectories with a two-digit number and a dash, to simplify the ordering of the files. To disable a configuration file supplied by the vendor, the recommended way is to place a symlink to /dev/null in the configuration directory in /etc/, with the same filename as the vendor configuration file.OPTIONS
All options are configured in the [Journal] section: Storage=Controls where to store journal data. One of
"volatile", "persistent", "auto" and
"none". If "volatile", journal log data will be stored
only in memory, i.e. below the /run/log/journal hierarchy (which is created if
needed). If "persistent", data will be stored preferably on disk,
i.e. below the /var/log/journal hierarchy (which is created if needed), with a
fallback to /run/log/journal (which is created if needed), during early boot
and if the disk is not writable. "auto" behaves like
"persistent" if the /var/log/journal directory exists, and
"volatile" otherwise (the existence of the directory controls the
storage mode). "none" turns off all storage, all log data received
will be dropped (but forwarding to other targets, such as the console, the
kernel log buffer, or a syslog socket will still work). Defaults to
"auto" in the default journal namespace, and "persistent"
in all others.
Note that journald will initially use volatile storage, until a call to
journalctl --flush (or sending SIGUSR1 to journald) will cause
it to switch to persistent logging (under the conditions mentioned above).
This is done automatically on boot via
"systemd-journal-flush.service".
Note that when this option is changed to "volatile", existing
persistent data is not removed. In the other direction, journalctl(1)
with the --flush option may be used to move volatile data to persistent
storage.
When journal namespacing (see LogNamespace= in systemd.exec(5)) is
used, setting Storage= to "volatile" or "auto" will
not have an effect on the creation of the per-namespace logs directory in
/var/log/journal/, as the [email protected] service file by default
carries LogsDirectory=. To turn that off, add a unit file drop-in file
that sets LogsDirectory= to an empty string.
Compress=
Can take a boolean value. If enabled (the
default), data objects that shall be stored in the journal and are larger than
the default threshold of 512 bytes are compressed before they are written to
the file system. It can also be set to a number of bytes to specify the
compression threshold directly. Suffixes like K, M, and G can be used to
specify larger units.
Seal=
Takes a boolean value. If enabled (the
default), and a sealing key is available (as created by journalctl(1)'s
--setup-keys command), Forward Secure Sealing (FSS) for all persistent
journal files is enabled. FSS is based on Seekable Sequential Key
Generators[1] by G. A. Marson and B. Poettering
(doi:10.1007/978-3-642-40203-6_7) and may be used to protect journal files
from unnoticed alteration.
SplitMode=
Controls whether to split up journal files per
user, either "uid" or "none". Split journal files are
primarily useful for access control: on UNIX/Linux access control is managed
per file, and the journal daemon will assign users read access to their
journal files. If "uid", all regular users (with UID outside the
range of system users, dynamic service users, and the nobody user) will each
get their own journal files, and system users will log to the system journal.
See Users, Groups, UIDs and GIDs on systemd systems[2] for more details
about UID ranges. If "none", journal files are not split up by user
and all messages are instead stored in the single system journal. In this mode
unprivileged users generally do not have access to their own log data. Note
that splitting up journal files by user is only available for journals stored
persistently. If journals are stored on volatile storage (see Storage=
above), only a single journal file is used. Defaults to "uid".
RateLimitIntervalSec=, RateLimitBurst=
Configures the rate limiting that is applied
to all messages generated on the system. If, in the time interval defined by
RateLimitIntervalSec=, more messages than specified in
RateLimitBurst= are logged by a service, all further messages within
the interval are dropped until the interval is over. A message about the
number of dropped messages is generated. This rate limiting is applied
per-service, so that two services which log do not interfere with each other's
limits. Defaults to 10000 messages in 30s. The time specification for
RateLimitIntervalSec= may be specified in the following units:
"s", "min", "h", "ms", "us".
To turn off any kind of rate limiting, set either value to 0.
Note that the effective rate limit is multiplied by a factor derived from the
available free disk space for the journal. Currently, this factor is
calculated using the base 2 logarithm.
Table 1. Example RateLimitBurst= rate modifications by
the available disk space
If a service provides rate limits for itself through
LogRateLimitIntervalSec= and/or LogRateLimitBurst= in
systemd.exec(5), those values will override the settings specified
here.
SystemMaxUse=, SystemKeepFree=, SystemMaxFileSize=,
SystemMaxFiles=, RuntimeMaxUse=, RuntimeKeepFree=,
RuntimeMaxFileSize=, RuntimeMaxFiles=
Available Disk Space | Burst Multiplier |
<= 1MB | 1 |
<= 16MB | 2 |
<= 256MB | 3 |
<= 4GB | 4 |
<= 64GB | 5 |
<= 1TB | 6 |
Enforce size limits on the journal files
stored. The options prefixed with "System" apply to the journal
files when stored on a persistent file system, more specifically
/var/log/journal. The options prefixed with "Runtime" apply to the
journal files when stored on a volatile in-memory file system, more
specifically /run/log/journal. The former is used only when /var/ is mounted,
writable, and the directory /var/log/journal exists. Otherwise, only the
latter applies. Note that this means that during early boot and if the
administrator disabled persistent logging, only the latter options apply,
while the former apply if persistent logging is enabled and the system is
fully booted up. journalctl and systemd-journald ignore all
files with names not ending with ".journal" or
".journal~", so only such files, located in the appropriate
directories, are taken into account when calculating current disk usage.
SystemMaxUse= and RuntimeMaxUse= control how much disk space the
journal may use up at most. SystemKeepFree= and RuntimeKeepFree=
control how much disk space systemd-journald shall leave free for other uses.
systemd-journald will respect both limits and use the smaller of the
two values.
The first pair defaults to 10% and the second to 15% of the size of the
respective file system, but each value is capped to 4G. If the file system is
nearly full and either SystemKeepFree= or RuntimeKeepFree= are
violated when systemd-journald is started, the limit will be raised to the
percentage that is actually free. This means that if there was enough free
space before and journal files were created, and subsequently something else
causes the file system to fill up, journald will stop using more space, but it
will not be removing existing files to reduce the footprint again, either.
Also note that only archived files are deleted to reduce the space occupied by
journal files. This means that, in effect, there might still be more space
used than SystemMaxUse= or RuntimeMaxUse= limit after a
vacuuming operation is complete.
SystemMaxFileSize= and RuntimeMaxFileSize= control how large
individual journal files may grow at most. This influences the granularity in
which disk space is made available through rotation, i.e. deletion of historic
data. Defaults to one eighth of the values configured with
SystemMaxUse= and RuntimeMaxUse= capped to 128M, so that usually
seven rotated journal files are kept as history. If the journal compact mode
is enabled (enabled by default), the maximum file size is capped to 4G.
Specify values in bytes or use K, M, G, T, P, E as units for the specified sizes
(equal to 1024, 1024², ... bytes). Note that size limits are enforced
synchronously when journal files are extended, and no explicit rotation step
triggered by time is needed.
SystemMaxFiles= and RuntimeMaxFiles= control how many individual
journal files to keep at most. Note that only archived files are deleted to
reduce the number of files until this limit is reached; active files will stay
around. This means that, in effect, there might still be more journal files
around in total than this limit after a vacuuming operation is complete. This
setting defaults to 100.
MaxFileSec=
The maximum time to store entries in a single
journal file before rotating to the next one. Normally, time-based rotation
should not be required as size-based rotation with options such as
SystemMaxFileSize= should be sufficient to ensure that journal files do
not grow without bounds. However, to ensure that not too much data is lost at
once when old journal files are deleted, it might make sense to change this
value from the default of one month. Set to 0 to turn off this feature. This
setting takes time values which may be suffixed with the units
"year", "month", "week", "day",
"h" or "m" to override the default time unit of
seconds.
MaxRetentionSec=
The maximum time to store journal entries.
This controls whether journal files containing entries older than the
specified time span are deleted. Normally, time-based deletion of old journal
files should not be required as size-based deletion with options such as
SystemMaxUse= should be sufficient to ensure that journal files do not
grow without bounds. However, to enforce data retention policies, it might
make sense to change this value from the default of 0 (which turns off this
feature). This setting also takes time values which may be suffixed with the
units "year", "month", "week", "day",
"h" or " m" to override the default time unit of
seconds.
SyncIntervalSec=
The timeout before synchronizing journal files
to disk. After syncing, journal files are placed in the OFFLINE state. Note
that syncing is unconditionally done immediately after a log message of
priority CRIT, ALERT or EMERG has been logged. This setting hence applies only
to messages of the levels ERR, WARNING, NOTICE, INFO, DEBUG. The default
timeout is 5 minutes.
ForwardToSyslog=, ForwardToKMsg=, ForwardToConsole=,
ForwardToWall=
Control whether log messages received by the
journal daemon shall be forwarded to a traditional syslog daemon, to the
kernel log buffer (kmsg), to the system console, or sent as wall messages to
all logged-in users. These options take boolean arguments. If forwarding to
syslog is enabled but nothing reads messages from the socket, forwarding to
syslog has no effect. By default, only forwarding to syslog and wall is
enabled. These settings may be overridden at boot time with the kernel command
line options "systemd.journald.forward_to_syslog",
"systemd.journald.forward_to_kmsg",
"systemd.journald.forward_to_console", and
"systemd.journald.forward_to_wall". If the option name is specified
without "=" and the following argument, true is assumed. Otherwise,
the argument is parsed as a boolean.
When forwarding to the console, the TTY to log to can be changed with
TTYPath=, described below.
When forwarding to the kernel log buffer (kmsg), make sure to select a suitably
large size for the log buffer, for example by adding
"log_buf_len=8M" to the kernel command line. systemd will
automatically disable kernel's rate-limiting applied to userspace processes
(equivalent to setting "printk.devkmsg=on").
Note: Forwarding is performed synchronously within journald, and may
significantly affect its performance. This is particularly relevant when using
ForwardToConsole=yes in cloud environments, where the console is often a slow,
virtual serial port. Since journald is implemented as a conventional
single-process daemon, forwarding to a completely hung console will block
journald. This can have a cascading effect resulting in any services
synchronously logging to the blocked journal also becoming blocked. Unless
actively debugging/developing something, it's generally preferable to setup a
journalctl --follow style service redirected to the console, instead of
ForwardToConsole=yes, for production use.
MaxLevelStore=, MaxLevelSyslog=, MaxLevelKMsg=,
MaxLevelConsole=, MaxLevelWall=
Controls the maximum log level of messages
that are stored in the journal, forwarded to syslog, kmsg, the console or wall
(if that is enabled, see above). As argument, takes one of "emerg",
"alert", "crit", "err", "warning",
"notice", "info", "debug", or integer values in
the range of 0–7 (corresponding to the same levels). Messages equal or
below the log level specified are stored/forwarded, messages above are
dropped. Defaults to "debug" for MaxLevelStore= and
MaxLevelSyslog=, to ensure that the all messages are stored in the
journal and forwarded to syslog. Defaults to "notice" for
MaxLevelKMsg=, "info" for MaxLevelConsole=, and
"emerg" for MaxLevelWall=. These settings may be overridden
at boot time with the kernel command line options
"systemd.journald.max_level_store=",
"systemd.journald.max_level_syslog=",
"systemd.journald.max_level_kmsg=",
"systemd.journald.max_level_console=",
"systemd.journald.max_level_wall=".
ReadKMsg=
Takes a boolean value. If enabled
systemd-journal processes /dev/kmsg messages generated by the kernel.
In the default journal namespace this option is enabled by default, it is
disabled in all others.
Audit=
Takes a boolean value. If enabled
systemd-journal will turn on kernel auditing on start-up. If disabled
it will turn it off. If unset it will neither enable nor disable it, leaving
the previous state unchanged. Note that this option does not control whether
systemd-journald collects generated audit records, it just controls
whether it tells the kernel to generate them. This means if another tool turns
on auditing even if systemd-journald left it off, it will still collect
the generated messages. Defaults to off.
TTYPath=
Change the console TTY to use if
ForwardToConsole=yes is used. Defaults to /dev/console.
LineMax=
The maximum line length to permit when
converting stream logs into record logs. When a systemd unit's standard
output/error are connected to the journal via a stream socket, the data read
is split into individual log records at newline ("\n", ASCII 10) and
NUL characters. If no such delimiter is read for the specified number
of bytes a hard log record boundary is artificially inserted, breaking up
overly long lines into multiple log records. Selecting overly large values
increases the possible memory usage of the Journal daemon for each stream
client, as in the worst case the journal daemon needs to buffer the specified
number of bytes in memory before it can flush a new log record to disk. Also
note that permitting overly large line maximum line lengths affects
compatibility with traditional log protocols as log records might not fit
anymore into a single AF_UNIX or AF_INET datagram. Takes a size
in bytes. If the value is suffixed with K, M, G or T, the specified size is
parsed as Kilobytes, Megabytes, Gigabytes, or Terabytes (with the base 1024),
respectively. Defaults to 48K, which is relatively large but still small
enough so that log records likely fit into network datagrams along with extra
room for metadata. Note that values below 79 are not accepted and will be
bumped to 79.
FORWARDING TO TRADITIONAL SYSLOG DAEMONS
Journal events can be transferred to a different logging daemon in two different ways. With the first method, messages are immediately forwarded to a socket (/run/systemd/journal/syslog), where the traditional syslog daemon can read them. This method is controlled by the ForwardToSyslog= option. With a second method, a syslog daemon behaves like a normal journal client, and reads messages from the journal files, similarly to journalctl(1). With this, messages do not have to be read immediately, which allows a logging daemon which is only started late in boot to access all messages since the start of the system. In addition, full structured meta-data is available to it. This method of course is available only if the messages are stored in a journal file at all. So it will not work if Storage=none is set. It should be noted that usually the second method is used by syslog daemons, so the Storage= option, and not the ForwardToSyslog= option, is relevant for them.SEE ALSO
systemd(1), systemd-journald.service(8), journalctl(1), systemd.journal-fields(7), systemd-system.conf(5)NOTES
- 1.
- Seekable Sequential Key Generators
- 2.
- Users, Groups, UIDs and GIDs on systemd systems
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