</para>
<para>Log data collected by the journal is primarily
- text based but can also include binary data where
+ 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
+ <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
+ <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 AF_UNIX
- SOCK_DGRAM socket
- <filename>/run/systemd/journal/syslog</filename> (if it exists) which
- may be used by UNIX syslog daemons to process the data
+ 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
is flushed to
<filename>/var/</filename> in order to
make it persistent (if this is
- enabled). This may be used after
+ enabled). This must be used after
<filename>/var/</filename> is mounted,
- but is generally not required since
- the first journal write when
- <filename>/var/</filename> becomes
- writable triggers the flushing
- anyway.</para></listitem>
+ as otherwise log data from
+ <filename>/run</filename> is never
+ flushed to <filename>/var</filename>
+ regardless of the
+ configuration.</para></listitem>
</varlistentry>
<varlistentry>
<filename>journald.conf</filename> may be overridden on
the kernel command line:</para>
- <variablelist>
+ <variablelist class='kernel-commandline-options'>
<varlistentry>
<term><varname>systemd.journald.forward_to_syslog=</varname></term>
<term><varname>systemd.journald.forward_to_kmsg=</varname></term>
</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>
<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>sd-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>setfacl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <command>pydoc systemd.journal</command>.
</para>
</refsect1>
~ianmdlvl / elogind.git / blobdiff