'\" t
.TH "SYSTEMD\-JOURNALD\&.SERVICE" "8" "" "systemd 204" "systemd-journald.service"
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.SH "NAME"
systemd-journald.service, systemd-journald.socket, systemd-journald \- Journal service
.SH "SYNOPSIS"
.PP
systemd\-journald\&.service
.PP
systemd\-journald\&.socket
.PP
/usr/lib/systemd/systemd\-journald
.SH "DESCRIPTION"
.PP
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
\fBsyslog\fR(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
\fBsystemd.journal-fields\fR(7)
for more information about the collected meta data\&.
.PP
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\&.
.PP
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\&.
.PP
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\&.
.PP
See
\fBjournald.conf\fR(5)
for information about the configuration of this service\&.
.SH "SIGNALS"
.PP
SIGUSR1
.RS 4
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\&.
.RE
.PP
SIGUSR2
.RS 4
Request immediate rotation of the journal files\&.
.RE
.SH "KERNEL COMMAND LINE"
.PP
A few configuration parameters from
journald\&.conf
may be overridden on the kernel command line:
.PP
\fIsystemd\&.journald\&.forward_to_syslog=\fR, \fIsystemd\&.journald\&.forward_to_kmsg=\fR, \fIsystemd\&.journald\&.forward_to_console=\fR
.RS 4
Enables/disables forwarding of collected log messages to syslog, the kernel log buffer or the system console\&.
.sp
See
\fBjournald.conf\fR(5)
for information about these settings\&.
.RE
.SH "ACCESS CONTROL"
.PP
Journal files are by default owned and readable by the
systemd\-journal
system group (but not writable)\&. Adding a user to this group thus enables her/him to read the journal files\&.
.PP
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\&.
.PP
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:
.sp
.if n \{\
.RS 4
.\}
.nf
# setfacl \-Rnm g:wheel:rx,d:g:wheel:rx,g:adm:rx,d:g:adm:rx /var/log/journal/
.fi
.if n \{\
.RE
.\}
.PP
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\&.
.SH "SEE ALSO"
.PP

\fBsystemd\fR(1),
\fBjournalctl\fR(1),
\fBjournald.conf\fR(5),
\fBsystemd.journal-fields\fR(7),
\fBsd-journal\fR(3),
\fBsetfacl\fR(1)