doc: grammatical corrections

[elogind.git] / man / systemd.special.xml

diff --git a/man/systemd.special.xml b/man/systemd.special.xml
index b77b60d92048801f615593bae642ad71255cbaeb..f590b3fa1111b9c458d69f875bc7fa7d3c91472d 100644 (file)
--- a/man/systemd.special.xml
+++ b/man/systemd.special.xml
@@ -52,6 +52,7 @@
                 <filename>bluetooth.target</filename>,
                 <filename>ctrl-alt-del.target</filename>,
                 <filename>cryptsetup.target</filename>,
                 <filename>bluetooth.target</filename>,
                 <filename>ctrl-alt-del.target</filename>,
                 <filename>cryptsetup.target</filename>,

+                <filename>cryptsetup-pre.target</filename>,

                 <filename>dbus.service</filename>,
                 <filename>dbus.socket</filename>,
                 <filename>default.target</filename>,
                 <filename>dbus.service</filename>,
                 <filename>dbus.socket</filename>,
                 <filename>default.target</filename>,


@@ -71,6 +72,8 @@
                 <filename>local-fs-pre.target</filename>,
                 <filename>multi-user.target</filename>,
                 <filename>network.target</filename>,
                 <filename>local-fs-pre.target</filename>,
                 <filename>multi-user.target</filename>,
                 <filename>network.target</filename>,

+                <filename>network-online.target</filename>,
+                <filename>network-pre.target</filename>,

                 <filename>nss-lookup.target</filename>,
                 <filename>nss-user-lookup.target</filename>,
                 <filename>paths.target</filename>,
                 <filename>nss-lookup.target</filename>,
                 <filename>nss-user-lookup.target</filename>,
                 <filename>paths.target</filename>,


@@ -79,7 +82,6 @@
                 <filename>reboot.target</filename>,
                 <filename>remote-fs.target</filename>,
                 <filename>remote-fs-pre.target</filename>,
                 <filename>reboot.target</filename>,
                 <filename>remote-fs.target</filename>,
                 <filename>remote-fs-pre.target</filename>,

-                <filename>remote-fs-setup.target</filename>,

                 <filename>rescue.target</filename>,
                 <filename>initrd-root-fs.target</filename>,
                 <filename>rpcbind.target</filename>,
                 <filename>rescue.target</filename>,
                 <filename>initrd-root-fs.target</filename>,
                 <filename>rpcbind.target</filename>,


@@ -100,7 +102,11 @@
                 <filename>system-update.target</filename>,
                 <filename>time-sync.target</filename>,
                 <filename>timers.target</filename>,
                 <filename>system-update.target</filename>,
                 <filename>time-sync.target</filename>,
                 <filename>timers.target</filename>,

-                <filename>umount.target</filename></para>
+                <filename>umount.target</filename>,
+                <filename>-.slice</filename>,
+                <filename>system.slice</filename>,
+                <filename>user.slice</filename>,
+                <filename>machine.slice</filename></para>

         </refsynopsisdiv>
 
         <refsect1>
         </refsynopsisdiv>
 
         <refsect1>


@@ -314,7 +320,7 @@
                                         dependencies of type
                                         <varname>Before=</varname> to
                                         <filename>sysroot-usr.mount</filename>
                                         dependencies of type
                                         <varname>Before=</varname> to
                                         <filename>sysroot-usr.mount</filename>

-                                        and all mount points fround in
+                                        and all mount points found in

                                         <filename>/etc/fstab</filename>
                                         that have the
                                         <option>auto</option> and
                                         <filename>/etc/fstab</filename>
                                         that have the
                                         <option>auto</option> and


@@ -381,34 +387,72 @@
                                         this unit during
                                         installation. This is best
                                         configured via
                                         this unit during
                                         installation. This is best
                                         configured via

-                                        <varname>WantedBy=multi-uer.target</varname>
+                                        <varname>WantedBy=multi-user.target</varname>

                                         in the unit's
                                         <literal>[Install]</literal>
                                         section.</para>
                                 </listitem>
                         </varlistentry>
                         <varlistentry>
                                         in the unit's
                                         <literal>[Install]</literal>
                                         section.</para>
                                 </listitem>
                         </varlistentry>
                         <varlistentry>

-                                <term><filename>network.target</filename></term>
+                                <term><filename>network-online.target</filename></term>

                                 <listitem>
                                 <listitem>

-                                        <para>systemd automatically
-                                        adds dependencies of type
-                                        <varname>After=</varname> for
-                                        this target unit to all SysV
-                                        init script service units with
-                                        an LSB header referring to the
-                                        <literal>$network</literal>
-                                        facility.</para>
+                                        <para>Units that strictly
+                                        require a configured network
+                                        connection should pull in
+                                        <filename>network-online.target</filename>
+                                        (via a
+                                        <varname>Wants=</varname> type
+                                        dependency) and order
+                                        themselves after it. This
+                                        target unit is intended to
+                                        pull in a service that delays
+                                        further execution until the
+                                        network is sufficiently set
+                                        up. What precisely this
+                                        requires is left to the
+                                        implementation of the network
+                                        managing service.</para>

 
 

-                                        <para>This unit is supposed to
-                                        indicate when the network is
-                                        "up", but it is only very
-                                        loosely defined what that is
-                                        supposed to mean. Also see <ulink
+                                        <para>Note the distinction
+                                        between this unit and
+                                        <filename>network.target</filename>. This
+                                        unit is an active unit
+                                        (i.e. pulled in by the
+                                        consumer rather than the
+                                        provider of this
+                                        functionality) and pulls in a
+                                        service which possibly adds
+                                        substantial delays to further
+                                        execution. In contrast,
+                                        <filename>network.target</filename>
+                                        is a passive unit (i.e. pulled
+                                        in by the provider of the
+                                        functionality, rather than the
+                                        consumer) that usually does
+                                        not delay execution
+                                        much. Usually,
+                                        <filename>network.target</filename>
+                                        is part of the boot of most
+                                        systems, while
+                                        <filename>network-online.target</filename>
+                                        is not, except when at least
+                                        one unit requires it. Also see
+                                        <ulink

                                         url="http://www.freedesktop.org/wiki/Software/systemd/NetworkTarget">Running
                                         Services After the Network is
                                         up</ulink> for more
                                         information.</para>
                                         url="http://www.freedesktop.org/wiki/Software/systemd/NetworkTarget">Running
                                         Services After the Network is
                                         up</ulink> for more
                                         information.</para>

-                                </listitem>
+
+                                        <para>All mount units for
+                                        remote network file systems
+                                        automatically pull in this
+                                        unit, and order themselves
+                                        after it. Note that networking
+                                        daemons that simply provide
+                                        functionality to other hosts
+                                        generally do not need to pull
+                                        this in.</para>
+                                        </listitem>

                         </varlistentry>
                         <varlistentry>
                                 <term><filename>paths.target</filename></term>
                         </varlistentry>
                         <varlistentry>
                                 <term><filename>paths.target</filename></term>


@@ -481,29 +525,6 @@
                                         facility.</para>
                                 </listitem>
                         </varlistentry>
                                         facility.</para>
                                 </listitem>
                         </varlistentry>

-                        <varlistentry>
-                                <term><filename>remote-fs-setup.target</filename></term>
-                                <listitem>
-                                        <para>This target unit is
-                                        automatically pulled in (by a
-                                        <varname>Wants=</varname> type
-                                        dependency) by all remote
-                                        mount points. It can be used
-                                        to run certain units when at
-                                        least one remote file system
-                                        is to be mounted. Note that
-                                        this target is not ordered
-                                        against the remote mounts, use
-                                        <filename>remote-fs-pre.target</filename>
-                                        for that (see below).</para>
-
-                                        <para>Again, this target unit
-                                        is <emphasis>not</emphasis>
-                                        suitable for ordering, it is
-                                        only useful for pulling in
-                                        other units.</para>
-                                </listitem>
-                        </varlistentry>

                         <varlistentry>
                                 <term><filename>rescue.target</filename></term>
                                 <listitem>
                         <varlistentry>
                                 <term><filename>rescue.target</filename></term>
                                 <listitem>


@@ -769,7 +790,7 @@
                                         available at boot.</para>
 
                                         <para>This may be used to pull
                                         available at boot.</para>
 
                                         <para>This may be used to pull

-                                        in printer management
+                                        in smartcard management

                                         daemons dynamically when
                                         smartcard hardware is
                                         found.</para>
                                         daemons dynamically when
                                         smartcard hardware is
                                         found.</para>


@@ -786,7 +807,7 @@
 
                                         <para>This may be used to pull
                                         in audio management daemons
 
                                         <para>This may be used to pull
                                         in audio management daemons

-                                        dynamically when printer
+                                        dynamically when audio

                                         hardware is found.</para>
                                 </listitem>
                         </varlistentry>
                                         hardware is found.</para>
                                 </listitem>
                         </varlistentry>


@@ -801,7 +822,7 @@
                 services. These targets are generally not part of the
                 initial boot transaction, unless they are explicitly
                 pulled in by one of the implementing services. Note
                 services. These targets are generally not part of the
                 initial boot transaction, unless they are explicitly
                 pulled in by one of the implementing services. Note

-                specifically, that these <emphasis>passive</emphasis>
+                specifically that these <emphasis>passive</emphasis>

                 target units are generally not pulled in by the
                 consumer of a service, but by the provider of the
                 service. This means: a consuming service should order
                 target units are generally not pulled in by the
                 consumer of a service, but by the provider of the
                 service. This means: a consuming service should order


@@ -811,7 +832,36 @@
                 (via a <varname>Wants=</varname> type
                 dependency).</para>
 
                 (via a <varname>Wants=</varname> type
                 dependency).</para>
 

+                <para>Note that these passive units cannot be started
+                manually, i.e. <literal>systemctl start
+                time-sync.target</literal> will fail with an
+                error. They can only be pulled in by dependency. This
+                is enforced since they exist for ordering purposes
+                only and thus are not useful as only unit within a
+                transaction.</para>
+

                 <variablelist>
                 <variablelist>

+                        <varlistentry>
+                                <term><filename>cryptsetup-pre.target</filename></term>
+                                <listitem>
+                                        <para>This passive target unit
+                                        may be pulled in by services
+                                        that want to run before any
+                                        encrypted block device is set
+                                        up. All encrypted block
+                                        devices are set up after this
+                                        target has been reached. Since
+                                        the shutdown order is
+                                        implicitly the reverse
+                                        start-up order between units,
+                                        this target is particularly
+                                        useful to ensure that a
+                                        service is shut down only
+                                        after all encrypted block
+                                        devices are fully
+                                        stopped.</para>
+                                </listitem>
+                        </varlistentry>

                         <varlistentry>
                                 <term><filename>local-fs-pre.target</filename></term>
                                 <listitem>
                         <varlistentry>
                                 <term><filename>local-fs-pre.target</filename></term>
                                 <listitem>


@@ -824,6 +874,59 @@
                                         all local mounts.</para>
                                 </listitem>
                         </varlistentry>
                                         all local mounts.</para>
                                 </listitem>
                         </varlistentry>

+                        <varlistentry>
+                                <term><filename>network.target</filename></term>
+                                <listitem>
+                                        <para>This unit is supposed to
+                                        indicate when network
+                                        functionality is available,
+                                        but it is only very weakly
+                                        defined what that is supposed
+                                        to mean, with one exception:
+                                        at shutdown, a unit that is
+                                        ordered after
+                                        <filename>network.target</filename>
+                                        will be stopped before the
+                                        network -- to whatever level
+                                        it might be set up then -- is
+                                        shut down. It is hence useful
+                                        when writing service files
+                                        that require network access on
+                                        shutdown, which should order
+                                        themselves after this target,
+                                        but not pull it in. Also see
+                                        <ulink
+                                        url="http://www.freedesktop.org/wiki/Software/systemd/NetworkTarget">Running
+                                        Services After the Network is
+                                        up</ulink> for more
+                                        information. Also see
+                                        <filename>network-online.target</filename>
+                                        described above.</para>
+
+                                        <para>systemd automatically
+                                        adds dependencies of type
+                                        <varname>After=</varname> for
+                                        this target unit to all SysV
+                                        init script service units with
+                                        an LSB header referring to the
+                                        <literal>$network</literal>
+                                        facility.</para>
+                                </listitem>
+                        </varlistentry>
+                        <varlistentry>
+                                <term><filename>network-pre.target</filename></term>
+                                <listitem>
+                                        <para>This passive target unit
+                                        may be pulled in by services
+                                        that want to run before any
+                                        network is set up, for example
+                                        for the purpose of setting up a
+                                        firewall. All network
+                                        management software orders
+                                        itself after this target, but
+                                        does not pull it in.</para>
+                                </listitem>
+                        </varlistentry>

                         <varlistentry>
                                 <term><filename>nss-lookup.target</filename></term>
                                 <listitem>
                         <varlistentry>
                                 <term><filename>nss-lookup.target</filename></term>
                                 <listitem>


@@ -835,7 +938,12 @@
                                         user/group name lookups for
                                         which
                                         <filename>nss-user-lookup.target</filename>
                                         user/group name lookups for
                                         which
                                         <filename>nss-user-lookup.target</filename>

-                                        should be used. systemd
+                                        should be used. All services
+                                        for which the availability of
+                                        full host/network name
+                                        resolution is essential should
+                                        be ordered after this target,
+                                        but not pull it in. systemd

                                         automatically adds
                                         dependencies of type
                                         <varname>After=</varname> for
                                         automatically adds
                                         dependencies of type
                                         <varname>After=</varname> for


@@ -857,7 +965,16 @@
                                         host/network name lookups for
                                         which
                                         <filename>nss-lookup.target</filename>
                                         host/network name lookups for
                                         which
                                         <filename>nss-lookup.target</filename>

-                                        should be used. </para>
+                                        should be used. All services
+                                        for which the availability of
+                                        the full user/group database is
+                                        essential should be ordered
+                                        after this target, but not
+                                        pull it in. Note that system
+                                        users are always resolvable,
+                                        and hence do not require any
+                                        special ordering against this
+                                        target.</para>

                                 </listitem>
                         </varlistentry>
                         <varlistentry>
                                 </listitem>
                         </varlistentry>
                         <varlistentry>


@@ -878,23 +995,22 @@
                                         <varname>Wants=</varname> type
                                         dependency. If the unit wants
                                         to be pulled in by the first
                                         <varname>Wants=</varname> type
                                         dependency. If the unit wants
                                         to be pulled in by the first

-                                        remote mount showing up it
+                                        remote mount showing up, it

                                         should use
                                         should use

-                                        <filename>remote-fs-setup.target</filename>
+                                        <filename>network-online.target</filename>

                                         (see above).</para>
                                         (see above).</para>

-
-                                        <para>Again, this target unit
-                                        is <emphasis>not</emphasis>
-                                        suitable for pulling in other
-                                        units, it is only useful for
-                                        ordering.</para>

                                 </listitem>
                         </varlistentry>
                         <varlistentry>
                                 <term><filename>rpcbind.target</filename></term>
                                 <listitem>
                                 </listitem>
                         </varlistentry>
                         <varlistentry>
                                 <term><filename>rpcbind.target</filename></term>
                                 <listitem>

-                                        <para>systemd automatically
-                                        adds dependencies of type
+                                        <para>The portmapper/rpcbind
+                                        pulls in this target and
+                                        orders itself before it, to
+                                        indicate its
+                                        availability. systemd
+                                        automatically adds
+                                        dependencies of type

                                         <varname>After=</varname> for
                                         this target unit to all SysV
                                         init script service units with
                                         <varname>After=</varname> for
                                         this target unit to all SysV
                                         init script service units with


@@ -906,14 +1022,24 @@
                         <varlistentry>
                                 <term><filename>time-sync.target</filename></term>
                                 <listitem>
                         <varlistentry>
                                 <term><filename>time-sync.target</filename></term>
                                 <listitem>

-                                        <para>systemd automatically
-                                        adds dependencies of type
+                                        <para>Services responsible for
+                                        synchronizing the system clock
+                                        from a remote source (such as
+                                        NTP client implementations)
+                                        should pull in this target and
+                                        order themselves before
+                                        it. All services where correct
+                                        time is essential should be
+                                        ordered after this unit, but
+                                        not pull it in. systemd
+                                        automatically adds
+                                        dependencies of type

                                         <varname>After=</varname> for
                                         this target unit to all SysV
                                         init script service units with
                                         an LSB header referring to the
                                         <literal>$time</literal>
                                         <varname>After=</varname> for
                                         this target unit to all SysV
                                         init script service units with
                                         an LSB header referring to the
                                         <literal>$time</literal>

-                                        facility.</para>
+                                        facility. </para>

                                 </listitem>
                         </varlistentry>
                 </variablelist>
                                 </listitem>
                         </varlistentry>
                 </variablelist>


@@ -935,7 +1061,7 @@
                 <filename>smartcard.target</filename>,
                 <filename>sound.target</filename>.</para>
 
                 <filename>smartcard.target</filename>,
                 <filename>sound.target</filename>.</para>
 

-                <para>In addition the following special unit is
+                <para>In addition, the following special unit is

                 understood only when systemd runs as service instance:</para>
 
                 <variablelist>
                 understood only when systemd runs as service instance:</para>
 
                 <variablelist>


@@ -950,8 +1076,8 @@
                                         terminate the user service
                                         manager should start this
                                         unit. If systemd receives
                                         terminate the user service
                                         manager should start this
                                         unit. If systemd receives

-                                        SIGTERM or SIGINT when running
-                                        as user service daemon it will
+                                        <constant>SIGTERM</constant> or <constant>SIGINT</constant> when running
+                                        as user service daemon, it will

                                         start this unit.</para>
 
                                         <para>Normally, this pulls in
                                         start this unit.</para>
 
                                         <para>Normally, this pulls in


@@ -965,6 +1091,63 @@
                 </variablelist>
         </refsect1>
 
                 </variablelist>
         </refsect1>
 

+        <refsect1>
+                <title>Special Slice Units</title>
+
+                <para>There are four <literal>.slice</literal> units
+                which form the basis of the hierarchy for assignment
+                of resources for services, users, and virtual machines
+                or containers.</para>
+
+                <variablelist>
+                        <varlistentry>
+                                <term><filename>-.slice</filename></term>
+                                <listitem>
+                                        <para>The root slice is the
+                                        root of the hierarchy. It
+                                        usually does not contain units
+                                        directly, but may be used to
+                                        set defaults for the whole
+                                        tree.</para>
+                                </listitem>
+                        </varlistentry>
+
+                        <varlistentry>
+                                <term><filename>system.slice</filename></term>
+                                <listitem>
+                                        <para>By default, all services
+                                        services started by
+                                        <command>systemd</command> are
+                                        found in this slice.</para>
+                                </listitem>
+                        </varlistentry>
+
+                        <varlistentry>
+                                <term><filename>user.slice</filename></term>
+                                <listitem>
+                                        <para>By default, all user
+                                        processes and services started
+                                        on behalf of the user,
+                                        including the per-user systemd
+                                        instance are found in this
+                                        slice.</para>
+                                </listitem>
+                        </varlistentry>
+
+                        <varlistentry>
+                                <term><filename>machine.slice</filename></term>
+                                <listitem>
+                                        <para>By default, all virtual
+                                        machines and containers
+                                        registered with
+                                        <command>systemd-machined</command>
+                                        are found in this slice.
+                                        </para>
+                                </listitem>
+                        </varlistentry>
+                </variablelist>
+        </refsect1>
+

         <refsect1>
                   <title>See Also</title>
                   <para>
         <refsect1>
                   <title>See Also</title>
                   <para>


@@ -973,6 +1156,7 @@
                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

+                          <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

                           <citerefentry><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
                   </para>
                           <citerefentry><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
                   </para>