<?xml version='1.0'?> <!--*-nxml-*-->
-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
-
-<!--
- SPDX-License-Identifier: LGPL-2.1+
-
- 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/>.
--->
+<!-- SPDX-License-Identifier: LGPL-2.1+ -->
<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>
<listitem><para>Structured system log messages via the native
Journal API, see
- <citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>4</manvolnum></citerefentry></para></listitem>
+ <citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>3</manvolnum></citerefentry></para></listitem>
<listitem><para>Standard output and standard error of service units. For further details see
below.</para></listitem>
<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. The
- <command>journalctl --flush</command> command uses this signal
- to request flushing of the journal files, and then waits for
+ <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. Use the
+ <command>journalctl --flush</command> command to request flushing of the journal files, and wait for
the operation to complete. See
- <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
- for details.</para></listitem>
+ <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> for
+ details.</para></listitem>
</varlistentry>
<varlistentry>
<term>SIGUSR2</term>
- <listitem><para>Request immediate rotation of the journal
- files. The <command>journalctl --rotate</command> command uses
- this signal to request journal file
- rotation.</para></listitem>
+ <listitem><para>Request immediate rotation of the journal files. Use the <command>journalctl
+ --rotate</command> command to request journal file rotation, and wait for the operation to
+ complete.</para></listitem>
</varlistentry>
<varlistentry>
<term>SIGRTMIN+1</term>
- <listitem><para>Request that all unwritten log data is written
- to disk. The <command>journalctl --sync</command> command uses
- this signal to trigger journal synchronization, and then waits
- for the operation to complete.</para></listitem>
+ <listitem><para>Request that all unwritten log data is written to disk. Use the <command>journalctl
+ --sync</command> command to trigger journal synchronization, and wait for the operation to
+ complete.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<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
+ writable. Adding a user to this group thus enables them 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
+ <para>By default, each user, with a UID outside the range of system users,
+ dynamic service users, and the nobody user, will get their own set of
+ journal files in <filename>/var/log/journal/</filename>. See
+ <ulink url="https://systemd.io/UIDS-GIDS">Users, Groups, UIDs and GIDs on systemd systems</ulink>
+ for more details about UID ranges. These journal
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>
<varlistentry>
<term><filename>/etc/systemd/journald.conf</filename></term>
- <listitem><para>Configure
- <command>systemd-journald</command>
- behavior. See
+ <listitem><para>Configure <command>systemd-journald</command> behavior. See
<citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para></listitem>
</varlistentry>
<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
+ <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>
<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>
+ configuration file.</para>
+
+ <para>When <filename>systemd-journald</filename> ceases writing to a journal file,
+ it will be renamed to <literal><replaceable>original-name</replaceable>@<replaceable>suffix.journal</replaceable></literal>
+ (or <literal><replaceable>original-name</replaceable>@<replaceable>suffix.journal~</replaceable></literal>).
+ Such files are "archived" and will not be written to any more.</para>
+
+ <para>In general, it is safe to read or copy any journal file (active or archived).
+ <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ and the functions in the
+ <citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ library should be able to read all entries that have been fully written.</para>
+
+ <para><filename>systemd-journald</filename> will automatically remove the oldest
+ archived journal files to limit disk use. See <varname>SystemMaxUse=</varname>
+ and related settings in
+ <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+ </para></listitem>
</varlistentry>
<varlistentry>
<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>,
+ <citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<command>pydoc systemd.journal</command>
</para>
</refsect1>
projects / thirdparty / systemd.git / blobdiff