JOURNALD.CONF(5)



JOURNALD.CONF(5)                 journald.conf                JOURNALD.CONF(5)

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

SYNOPSIS
       /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
       These files configure various parameters of the systemd journal
       service, systemd-journald.service(8). See systemd.syntax(5) 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
       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
       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" is similar to "persistent"
           but the directory /var/log/journal is not created if needed, so
           that its existence controls where log data goes.  "none" turns off
           all storage, all log data received will be dropped. Forwarding to
           other targets, such as the console, the kernel log buffer, or a
           syslog socket will still work however. Defaults to "auto" in the
           default journal namespace, and "persistent" in all others.

       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, 1024^2, ... 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").

       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
           https://eprint.iacr.org/2013/397

        2. Users, Groups, UIDs and GIDs on systemd systems
           https://systemd.io/UIDS-GIDS

systemd 245                                                   JOURNALD.CONF(5)

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