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-<?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">
-
-<!--
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-
- 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
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- 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>
~ianmdlvl / elogind.git / blobdiff