mirror of
https://github.com/systemd/systemd.git
synced 2024-12-26 03:22:00 +03:00
251 lines
10 KiB
XML
251 lines
10 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
|
|
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
|
|
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
|
|
|
|
<!--
|
|
This file is part of systemd.
|
|
|
|
Copyright 2010 Lennart Poettering
|
|
|
|
systemd is free software; you can redistribute it and/or modify it
|
|
under the terms of the GNU Lesser General Public License as published by
|
|
the Free Software Foundation; either version 2.1 of the License, or
|
|
(at your option) any later version.
|
|
|
|
systemd is distributed in the hope that it will be useful, but
|
|
WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License
|
|
along with systemd; If not, see <http://www.gnu.org/licenses/>.
|
|
-->
|
|
|
|
<refentry id="systemd-journald.service">
|
|
|
|
<refentryinfo>
|
|
<title>systemd-journald.service</title>
|
|
<productname>systemd</productname>
|
|
|
|
<authorgroup>
|
|
<author>
|
|
<contrib>Developer</contrib>
|
|
<firstname>Lennart</firstname>
|
|
<surname>Poettering</surname>
|
|
<email>lennart@poettering.net</email>
|
|
</author>
|
|
</authorgroup>
|
|
</refentryinfo>
|
|
|
|
<refmeta>
|
|
<refentrytitle>systemd-journald.service</refentrytitle>
|
|
<manvolnum>8</manvolnum>
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>systemd-journald.service</refname>
|
|
<refname>systemd-journald.socket</refname>
|
|
<refname>systemd-journald-dev-log.socket</refname>
|
|
<refname>systemd-journald</refname>
|
|
<refpurpose>Journal service</refpurpose>
|
|
</refnamediv>
|
|
|
|
<refsynopsisdiv>
|
|
<para><filename>systemd-journald.service</filename></para>
|
|
<para><filename>systemd-journald.socket</filename></para>
|
|
<para><filename>systemd-journald-dev-log.socket</filename></para>
|
|
<para><filename>/usr/lib/systemd/systemd-journald</filename></para>
|
|
</refsynopsisdiv>
|
|
|
|
<refsect1>
|
|
<title>Description</title>
|
|
|
|
<para><filename>systemd-journald</filename> 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:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem><para>Kernel log messages, via kmsg</para></listitem>
|
|
|
|
<listitem><para>Simple system log messages, via the libc
|
|
<citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
|
call</para></listitem>
|
|
|
|
<listitem><para>Structured system log messages via the native
|
|
Journal API, see
|
|
<citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>4</manvolnum></citerefentry></para></listitem>
|
|
|
|
<listitem><para>Standard output and standard error of system
|
|
services</para></listitem>
|
|
|
|
<listitem><para>Audit records, via the audit
|
|
subsystem</para></listitem>
|
|
</itemizedlist>
|
|
|
|
<para>The daemon will implicitly collect numerous metadata fields
|
|
for each log messages in a secure and unfakeable way. See
|
|
<citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
|
|
for more information about the collected metadata.
|
|
</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>By default, the journal stores log data in
|
|
<filename>/run/log/journal/</filename>. Since
|
|
<filename>/run/</filename> is volatile, log data is lost at
|
|
reboot. To make the data persistent, it is sufficient to create
|
|
<filename>/var/log/journal/</filename> where
|
|
<filename>systemd-journald</filename> will then store the
|
|
data.</para>
|
|
|
|
<para><filename>systemd-journald</filename> will forward all
|
|
received log messages to the
|
|
<constant>AF_UNIX</constant>/<constant>SOCK_DGRAM</constant>
|
|
socket <filename>/run/systemd/journal/syslog</filename>, if it
|
|
exists, which may be used by Unix syslog daemons to process the
|
|
data further.</para>
|
|
|
|
<para>See
|
|
<citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
|
for information about the configuration of this service.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Signals</title>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term>SIGUSR1</term>
|
|
|
|
<listitem><para>Request that journal data from
|
|
<filename>/run/</filename> is flushed to
|
|
<filename>/var/</filename> in order to make it persistent (if
|
|
this is enabled). This must be used after
|
|
<filename>/var/</filename> is mounted, as otherwise log data
|
|
from <filename>/run</filename> is never flushed to
|
|
<filename>/var</filename> regardless of the
|
|
configuration.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>SIGUSR2</term>
|
|
|
|
<listitem><para>Request immediate rotation of the journal
|
|
files.</para></listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Kernel Command Line</title>
|
|
|
|
<para>A few configuration parameters from
|
|
<filename>journald.conf</filename> may be overridden on the kernel
|
|
command line:</para>
|
|
|
|
<variablelist class='kernel-commandline-options'>
|
|
<varlistentry>
|
|
<term><varname>systemd.journald.forward_to_syslog=</varname></term>
|
|
<term><varname>systemd.journald.forward_to_kmsg=</varname></term>
|
|
<term><varname>systemd.journald.forward_to_console=</varname></term>
|
|
<term><varname>systemd.journald.forward_to_wall=</varname></term>
|
|
|
|
<listitem><para>Enables/disables forwarding of collected log
|
|
messages to syslog, the kernel log buffer, the system console
|
|
or wall.
|
|
</para>
|
|
|
|
<para>See
|
|
<citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
|
for information about these settings.</para>
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Access Control</title>
|
|
|
|
<para>Journal files are, by default, owned and readable by the
|
|
<literal>systemd-journal</literal> system group but are not
|
|
writable. Adding a user to this group thus enables her/him to read
|
|
the journal files.</para>
|
|
|
|
<para>By default, each logged in user will get her/his own set of
|
|
journal files in <filename>/var/log/journal/</filename>. 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.</para>
|
|
|
|
<para>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 <literal>wheel</literal> and <literal>adm</literal> system
|
|
groups with a command such as the following:</para>
|
|
|
|
<programlisting># setfacl -Rnm g:wheel:rx,d:g:wheel:rx,g:adm:rx,d:g:adm:rx /var/log/journal/</programlisting>
|
|
|
|
<para>Note that this command will update the ACLs both for
|
|
existing journal files and for future journal files created in the
|
|
<filename>/var/log/journal/</filename> directory.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Files</title>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><filename>/etc/systemd/journald.conf</filename></term>
|
|
|
|
<listitem><para>Configure
|
|
<command>systemd-journald</command>
|
|
behaviour. See
|
|
<citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><filename>/run/log/journal/<replaceable>machine-id</replaceable>/*.journal</filename></term>
|
|
<term><filename>/run/log/journal/<replaceable>machine-id</replaceable>/*.journal~</filename></term>
|
|
<term><filename>/var/log/journal/<replaceable>machine-id</replaceable>/*.journal</filename></term>
|
|
<term><filename>/var/log/journal/<replaceable>machine-id</replaceable>/*.journal~</filename></term>
|
|
|
|
<listitem><para><command>systemd-journald</command> writes
|
|
entries to files in
|
|
<filename>/run/log/journal/<replaceable>machine-id</replaceable>/</filename>
|
|
or
|
|
<filename>/var/log/journal/<replaceable>machine-id</replaceable>/</filename>
|
|
with the <literal>.journal</literal> suffix. If the daemon is
|
|
stopped uncleanly, or if the files are found to be corrupted,
|
|
they are renamed using the <literal>.journal~</literal>
|
|
suffix, and <command>systemd-journald</command> starts writing
|
|
to a new file. <filename>/run</filename> is used when
|
|
<filename>/var/log/journal</filename> is not available, or
|
|
when <option>Storage=volatile</option> is set in the
|
|
<citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
|
configuration file. </para></listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>See Also</title>
|
|
<para>
|
|
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd-coredump</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
|
|
<citerefentry project='die-net'><refentrytitle>setfacl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>4</manvolnum></citerefentry>,
|
|
<command>pydoc systemd.journal</command>.
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|