systemd-journald.service, systemd-journald.socket, systemd-journald — Journal service
systemd-journald.service
systemd-journald.socket
/usr/lib/systemd/systemd-journald
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 the kernel, from user processes via the libc
syslog(3)
call, from STDOUT/STDERR of system services or via its
native API. It will implicitly collect numerous meta
data fields for each log messages in a secure and
unfakeable way. See
systemd.journal-fields(7)
for more information about the collected meta data.
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.
Request that journal
data from /run/
is flushed to
/var/
in order to
make it persistent (if this is
enabled). This may be used after
/var/
is mounted,
but is generally not required since
the first journal write when
/var/
becomes
writable triggers the flushing
anyway.
Request immediate rotation of the journal files.
A few configuration parameters from
journald.conf
may be overriden on
the kernel command line:
systemd.journald.forward_to_syslog=
, systemd.journald.forward_to_kmsg=
, systemd.journald.forward_to_console=
Enables/disables forwarding of collected log messages to syslog, the kernel log buffer or the system console.
See journald.conf(5) for information about these settings.