journald.conf

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(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
       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 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
       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 247                                                     JOURNALD.CONF(5)