Descriptionsystemd-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
- syslog3
- 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
+ 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 syslog3
+ call
+
+ Structured system log messages via the
+ native Journal API, see
+ sd_journal_print4
+
+ 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-fields7
- for more information about the collected meta data.
+ for more information about the collected metadata.
Log data collected by the journal is primarily
@@ -77,7 +97,7 @@
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
+ 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
@@ -87,8 +107,7 @@
the data.systemd-journald will
- forward all received log messages to the AF_UNIX
- SOCK_DGRAM socket
+ 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.
@@ -142,11 +161,12 @@
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 or
- the system console.
+ to syslog, the kernel log buffer, the
+ system console or wall.
See
@@ -191,6 +211,52 @@
directory.
+
+ Files
+
+
+
+ /etc/systemd/journald.conf
+
+ Configure
+ systemd-journald
+ behaviour. See
+ journald.conf5.
+
+
+
+
+ /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
+ is
+ set in the
+ journald.conf5
+ configuration file.
+
+
+
+
+
See Also
@@ -199,7 +265,10 @@
journald.conf5,
systemd.journal-fields7,
sd-journal3,
- setfacl1
+ systemd-coredump8,
+ setfacl1,
+ sd_journal_print4,
+ pydoc systemd.journal.