journald.conf(5) — Linux manual page

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)

NAME         top

       journald.conf, journald.conf.d, journald@.conf - Journal service
       configuration files

SYNOPSIS         top

       /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

DESCRIPTION         top

       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.

CONFIGURATION DIRECTORIES AND PRECEDENCE         top

       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.

OPTIONS         top

       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.

FORWARDING TO TRADITIONAL SYSLOG DAEMONS         top

       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         top

       systemd(1), systemd-journald.service(8), journalctl(1),
       systemd.journal-fields(7), systemd-system.conf(5)

NOTES         top

        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

COLOPHON         top

       This page is part of the systemd (systemd system and service
       manager) project.  Information about the project can be found at
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have
       a bug report for this manual page, see
       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
       This page was obtained from the project's upstream Git repository
       ⟨https://github.com/systemd/systemd.git⟩ on 2020-12-18.  (At that
       time, the date of the most recent commit that was found in the
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       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

systemd 247                                             JOURNALD.CONF(5)

Pages that refer to this page: journalctl(1)coredump.conf(5)systemd.exec(5)systemd.directives(7)systemd.index(7)systemd.journal-fields(7)systemd.syntax(7)systemd-journald.service(8)