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NAME | SYNOPSIS | DESCRIPTION | CONFIGURATION DIRECTORIES AND PRECEDENCE | OPTIONS | FORWARDING TO TRADITIONAL SYSLOG DAEMONS | SEE ALSO | NOTES | COLOPHON |
JOURNALD.CONF(5) journald.conf JOURNALD.CONF(5)
journald.conf, journald.conf.d, journald@.conf - Journal service
configuration files
/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
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 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.
The default configuration is defined during compilation, so a
configuration file is only needed when it is necessary to deviate
from those defaults. By default, the configuration file in
/etc/systemd/ contains commented out entries showing the defaults as
a guide to the administrator. This file can be edited to create local
overrides.
When packages need to customize the configuration, they can install
configuration snippets in /usr/lib/systemd/*.conf.d/ or
/usr/local/lib/systemd/*.conf.d/. The main configuration file is read
before any of the configuration directories, and has the lowest
precedence; entries in a file in any configuration directory override
entries in the single 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 with the
lexicographically latest name takes precedence. For options which
accept a list of values, entries are collected as they occur in files
sorted lexicographically.
Files in /etc/ are reserved for the local administrator, who may use
this logic to override the configuration files installed by vendor
packages. 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.
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 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.
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
┌─────────────────────┬──────────────────┐
│Available Disk Space │ Burst Multiplier │
├─────────────────────┼──────────────────┤
│<= 1MB │ 1 │
├─────────────────────┼──────────────────┤
│<= 16MB │ 2 │
├─────────────────────┼──────────────────┤
│<= 256MB │ 3 │
├─────────────────────┼──────────────────┤
│<= 4GB │ 4 │
├─────────────────────┼──────────────────┤
│<= 64GB │ 5 │
├─────────────────────┼──────────────────┤
│<= 1TB │ 6 │
└─────────────────────┴──────────────────┘
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=
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=,
so that usually seven rotated journal files are kept as history.
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 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").
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
on.
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.
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.
systemd(1), systemd-journald.service(8), journalctl(1),
systemd.journal-fields(7), systemd-system.conf(5)
1. Seekable Sequential Key Generators
https://eprint.iacr.org/2013/397
2. Users, Groups, UIDs and GIDs on systemd systems
https://systemd.io/UIDS-GIDS
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⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩. This
page was obtained from the project's upstream Git repository
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systemd 246 JOURNALD.CONF(5)
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