SYSTEMD-JOURNALD.SERVICE(8) systemd-journald.service SYSTEMD-JOURNALD.SERVICE(8)
NAME
systemd-journald.service, systemd-journald.socket, systemd-journald - Journal service
SYNOPSIS
systemd-journald.service
systemd-journald.socket
/usr/lib/systemd/systemd-journald
DESCRIPTION
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.
systemd-journald will forward all received log messages to the AF_UNIX/SOCK_DGRAM socket
/run/systemd/journal/syslog, if it exists, which may be used by Unix syslog daemons to process the data
further.
See journald.conf(5) for information about the configuration of this service.
SIGNALS
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.
SIGUSR2
Request immediate rotation of the journal files.
KERNEL COMMAND LINE
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.
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
/etc/systemd/journald.conf
Configure systemd-journald behaviour. 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.
SEE ALSO
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.
systemd 219 SYSTEMD-JOURNALD.SERVICE(8)
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