NAME | SYNOPSIS | DESCRIPTION | SIGNALS | KERNEL COMMAND LINE | ACCESS CONTROL | FILES | SEE ALSO | COLOPHON

SYSTEMD-JOURNALD.SERVICE(8)ystemd-journald.serviceYSTEMD-JOURNALD.SERVICE(8)

NAME         top

       systemd-journald.service, systemd-journald.socket, systemd-journald-
       dev-log.socket, systemd-journald-audit.socket, systemd-journald -
       Journal service

SYNOPSIS         top

       systemd-journald.service

       systemd-journald.socket

       systemd-journald-dev-log.socket

       systemd-journald-audit.socket

       /usr/lib/systemd/systemd-journald

DESCRIPTION         top

       systemd-journald is a system service that collects and stores logging
       data. It creates and maintains structured, indexed journals based on
       logging information that is received from a variety of sources:

       ·   Kernel log messages, via kmsg

       ·   Simple system log messages, via the libc syslog(3) call

       ·   Structured system log messages via the native Journal API, see
           sd_journal_print(4)

       ·   Standard output and standard error of system services

       ·   Audit records, via the audit subsystem

       The daemon will implicitly collect numerous metadata fields for each
       log messages in a secure and unfakeable way. See
       systemd.journal-fields(7) for more information about the collected
       metadata.

       Log data collected by the journal is primarily text-based but can
       also include binary data where necessary. All objects stored in the
       journal can be up to 2^64-1 bytes in size.

       By default, the journal stores log data in /run/log/journal/. Since
       /run/ is volatile, log data is lost at reboot. To make the data
       persistent, it is sufficient to create /var/log/journal/ where
       systemd-journald will then store the data:

           mkdir -p /var/log/journal
           systemd-tmpfiles --create --prefix /var/log/journal

       See journald.conf(5) for information about the configuration of this
       service.

SIGNALS         top

       SIGUSR1
           Request that journal data from /run/ is flushed to /var/ in order
           to make it persistent (if this is enabled). This must be used
           after /var/ is mounted, as otherwise log data from /run is never
           flushed to /var regardless of the configuration. The journalctl
           --flush command uses this signal to request flushing of the
           journal files, and then waits for the operation to complete. See
           journalctl(1) for details.

       SIGUSR2
           Request immediate rotation of the journal files. The journalctl
           --rotate command uses this signal to request journal file
           rotation.

       SIGRTMIN+1
           Request that all unwritten log data is written to disk. The
           journalctl --sync command uses this signal to trigger journal
           synchronization, and then waits for the operation to complete.

KERNEL COMMAND LINE         top

       A few configuration parameters from journald.conf may be overridden
       on the kernel command line:

       systemd.journald.forward_to_syslog=,
       systemd.journald.forward_to_kmsg=,
       systemd.journald.forward_to_console=,
       systemd.journald.forward_to_wall=
           Enables/disables forwarding of collected log messages to syslog,
           the kernel log buffer, the system console or wall.

           See journald.conf(5) for information about these settings.

ACCESS CONTROL         top

       Journal files are, by default, owned and readable by the
       "systemd-journal" system group but are not writable. Adding a user to
       this group thus enables her/him to read the journal files.

       By default, each logged in user will get her/his own set of journal
       files in /var/log/journal/. These files will not be owned by the
       user, however, in order to avoid that the user can write to them
       directly. Instead, file system ACLs are used to ensure the user gets
       read access only.

       Additional users and groups may be granted access to journal files
       via file system access control lists (ACL). Distributions and
       administrators may choose to grant read access to all members of the
       "wheel" and "adm" system groups with a command such as the following:

           # setfacl -Rnm g:wheel:rx,d:g:wheel:rx,g:adm:rx,d:g:adm:rx /var/log/journal/

       Note that this command will update the ACLs both for existing journal
       files and for future journal files created in the /var/log/journal/
       directory.

FILES         top

       /etc/systemd/journald.conf
           Configure systemd-journald behavior. See journald.conf(5).

       /run/log/journal/machine-id/*.journal,
       /run/log/journal/machine-id/*.journal~,
       /var/log/journal/machine-id/*.journal,
       /var/log/journal/machine-id/*.journal~
           systemd-journald writes entries to files in
           /run/log/journal/machine-id/ or /var/log/journal/machine-id/ with
           the ".journal" suffix. If the daemon is stopped uncleanly, or if
           the files are found to be corrupted, they are renamed using the
           ".journal~" suffix, and systemd-journald starts writing to a new
           file.  /run is used when /var/log/journal is not available, or
           when Storage=volatile is set in the journald.conf(5)
           configuration file.

       /dev/kmsg, /dev/log, /run/systemd/journal/dev-log,
       /run/systemd/journal/socket, /run/systemd/journal/stdout
           Sockets and other paths that systemd-journald will listen on that
           are visible in the file system. In addition to these, journald
           can listen for audit events using netlink.

SEE ALSO         top

       systemd(1), journalctl(1), journald.conf(5),
       systemd.journal-fields(7), sd-journal(3), systemd-coredump(8),
       setfacl(1), sd_journal_print(4), pydoc systemd.journal

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 2016-10-04.  If you dis‐
       cover any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page, or
       you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail
       to man-pages@man7.org

systemd 231                                      SYSTEMD-JOURNALD.SERVICE(8)