man: document automatic dependencies

For all units ensure there's an "Automatic Dependencies" section in the
man page, and explain which dependencies are automatically added in all
cases, and which ones are added on top if DefaultDependencies=yes is
set.

This is also done for systemd.exec(5), systemd.resource-control(5) and
systemd.unit(5) as these pages describe common behaviour of various unit
types.

man/systemd.automount.xml

@@ -85,10 +85,24 @@
 
     <para>Automount units may be used to implement on-demand mounting
     as well as parallelized mounting of file systems.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>If an automount unit is beneath another mount unit in the
+    file system hierarchy, both a requirement and an ordering
+    dependency between both units are created automatically.</para>
+
+    <para>An implicit <varname>Before=</varname> dependency is created
+    between an automount unit and the mount unit it activates.</para>
+
+    <para>Automount units acquire automatic <varname>Before=</varname>
+    and <varname>Conflicts=</varname> on
+    <filename>umount.target</filename> in order to be stopped during
+    shutdown, unless <varname>DefaultDependencies=no</varname> is
+    set.</para>
 
-    <para>If an automount point is beneath another mount point in the
-    file system hierarchy, a dependency between both units is created
-    automatically.</para>
   </refsect1>
 
   <refsect1>

man/systemd.device.xml

@@ -83,7 +83,18 @@
     the escaping logic used to convert a file system path to a unit
     name see
     <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+  </refsect1>
 
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>Many unit types automatically acquire dependencies on device
+    units of devices they require. For example,
+    <filename>.socket</filename> unit acquire dependencies on the
+    device units of the network interface specified in
+    <varname>BindToDevice=</varname>. Similar, swap and mount units
+    acquire dependencies on the units encapsulating their backing
+    block devices.</para>
   </refsect1>
 
   <refsect1>

man/systemd.exec.xml

@@ -76,6 +76,31 @@
     unit type.</para>
   </refsect1>
 
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>A few execution parameters result in additional, automatic
+    dependencies to be added.</para>
+
+    <para>Units with <varname>WorkingDirectory=</varname> or
+    <varname>RootDirectory=</varname> set automatically gain
+    dependencies of type <varname>Requires=</varname> and
+    <varname>After=</varname> on all mount units required to access
+    the specified paths. This is equivalent to having them listed
+    explicitly in <varname>RequiresMountsFor=</varname>.</para>
+
+    <para>Similar, units with <varname>PrivateTmp=</varname> enabled
+    automatically get mount unit dependencies for all mounts
+    required to access <filename>/tmp</filename> and
+    <filename>/var/tmp</filename>.</para>
+
+    <para>Units whose output standard output or error output is
+    connected to any other sink but <option>null</option>,
+    <option>tty</option> and <option>socket</option> automatically
+    acquire dependencies of type <varname>After=</varname> on
+    <filename>journald.socket</filename>.</para>
+  </refsect1>
+
   <refsect1>
     <title>Options</title>
 
@@ -93,7 +118,9 @@
         and the respective user's home directory if run as user. If
         the setting is prefixed with the <literal>-</literal>
         character, a missing working directory is not considered
-        fatal.</para></listitem>
+        fatal. Note that setting this parameter might result in
+        additional dependencies to be added to the unit (see
+        above).</para></listitem>
       </varlistentry>
 
       <varlistentry>
@@ -104,7 +131,9 @@
         project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
         system call. If this is used, it must be ensured that the
         process binary and all its auxiliary files are available in
-        the <function>chroot()</function> jail.</para></listitem>
+        the <function>chroot()</function> jail. Note that setting this
+        parameter might result in additional dependencies to be added
+        to the unit (see above).</para></listitem>
       </varlistentry>
 
       <varlistentry>
@@ -351,6 +380,7 @@
         <para>This setting defaults to
         <option>null</option>.</para></listitem>
       </varlistentry>
+
       <varlistentry>
         <term><varname>StandardOutput=</varname></term>
         <listitem><para>Controls where file descriptor 1 (STDOUT) of
@@ -416,8 +446,11 @@
         <para>This setting defaults to the value set with
         <option>DefaultStandardOutput=</option> in
         <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
-        which defaults to <option>journal</option>.</para></listitem>
+        which defaults to <option>journal</option>. Note that setting
+        this parameter might result in additional dependencies to be
+        added to the unit (see above).</para></listitem>
       </varlistentry>
+
       <varlistentry>
         <term><varname>StandardError=</varname></term>
         <listitem><para>Controls where file descriptor 2 (STDERR) of
@@ -428,8 +461,11 @@
         standard error. This setting defaults to the value set with
         <option>DefaultStandardError=</option> in
         <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
-        which defaults to <option>inherit</option>.</para></listitem>
+        which defaults to <option>inherit</option>. Note that setting
+        this parameter might result in additional dependencies to be
+        added to the unit (see above).</para></listitem>
       </varlistentry>
+
       <varlistentry>
         <term><varname>TTYPath=</varname></term>
         <listitem><para>Sets the terminal device node to use if

man/systemd.mount.xml

@@ -94,10 +94,6 @@
     unit, to allow on-demand or parallelized mounting. See
     <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 
-    <para>If a mount point is beneath another mount point in the file
-    system hierarchy, a dependency between both units is created
-    automatically.</para>
-
     <para>Mount points created at runtime (independently of unit files
     or <filename>/etc/fstab</filename>) will be monitored by systemd
     and appear like any other mount unit in systemd. See
@@ -113,6 +109,52 @@
     File Systems</ulink>.</para>
   </refsect1>
 
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>If a mount unit is beneath another mount unit in the file
+    system hierarchy, both a requirement dependency and an ordering
+    dependency between both units are created automatically.</para>
+
+    <para>Block device backed file systems automatically gain
+    <varname>BindsTo=</varname> and <varname>After=</varname> type
+    dependencies on the device unit encapsulating the block
+    device (see below).</para>
+
+    <para>If traditional file system quota is enabled for a mount
+    unit, automatic <varname>Wants=</varname> and
+    <varname>Before=</varname> dependencies on
+    <filename>systemd-quotacheck.service</filename> and
+    <filename>quotaon.service</filename> are added.</para>
+
+    <para>For mount units with
+    <varname>DefaultDependencies=yes</varname> (the default) a couple
+    additional dependencies are added. Mount units referring to local
+    file systems automatically gain an <varname>After=</varname>
+    dependency on <filename>local-fs-pre.target</filename>. Network
+    mount units automatically acquire <varname>After=</varname>
+    dependencies on <filename>remote-fs-pre.target</filename>,
+    <filename>network.target</filename> and
+    <filename>network-online.target</filename>. Towards the latter a
+    <varname>Wants=</varname> unit is added as well. Mount units
+    referring to local and network file systems are distinguished by
+    their file system type specification. In some cases this is not
+    sufficient (for example network block device based mounts, such as
+    iSCSI), in which case <option>_netdev</option> may be added to the
+    mount option string of the unit, which forces systemd to consider the
+    mount unit a network mount. Mount units (regardless if local or
+    network) also acquire automatic <varname>Before=</varname> and
+    <varname>Conflicts=</varname> on
+    <filename>umount.target</filename> in order to be stopped
+    during shutdown.</para>
+
+    <para>Additional implicit dependencies may be added as result of
+    execution and resource control parameters as documented in
+    <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+    and
+    <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+  </refsect1>
+
   <refsect1>
     <title><filename>fstab</filename></title>
 
@@ -130,7 +172,7 @@
     <para>When reading <filename>/etc/fstab</filename> a few special
     mount options are understood by systemd which influence how
     dependencies are created for mount points. systemd will create a
-    dependency of type <option>Wants</option> or
+    dependency of type <varname>Wants=</varname> or
     <option>Requires</option> (see option <option>nofail</option>
     below), from either <filename>local-fs.target</filename> or
     <filename>remote-fs.target</filename>, depending whether the file

man/systemd.path.xml

@@ -79,13 +79,24 @@
     limitations as inotify, and for example cannot be used to monitor
     files or directories changed by other machines on remote NFS file
     systems.</para>
+  </refsect1>
 
-    <para>If a path unit is beneath another mount point in the file
+  <refsect1>
-    system hierarchy, a dependency between both units is created
+    <title>Automatic Dependencies</title>
-    automatically.</para>
+
+    <para>If a path unit is beneath another mount unit in the file
+    system hierarchy, both a requirement and an ordering dependency
+    between both units are created automatically.</para>
+
+    <para>An implicit <varname>Before=</varname> dependency is added
+    between a path unit and the unit it is supposed to activate.</para>
 
     <para>Unless <varname>DefaultDependencies=false</varname> is used,
     path units will implicitly have dependencies of type
+    <varname>Before=</varname> on <filename>paths.target</filename>,
+    dependencies of type <varname>After=</varname> and
+    <varname>Requires=</varname> on
+    <filename>sysinit.target</filename>, and have dependencies of type
     <varname>Conflicts=</varname> and <varname>Before=</varname> on
     <filename>shutdown.target</filename>. These ensure that path units
     are terminated cleanly prior to system shutdown. Only path units

man/systemd.resource-control.xml

@@ -89,6 +89,15 @@
     use of resource control APIs from programs.</para>
   </refsect1>
 
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>Units with the <varname>Slice=</varname> setting set get
+    automatic <varname>Requires=</varname> and
+    <varname>After=</varname> dependencies on the specified slice
+    unit.</para>
+  </refsect1>
+
   <refsect1>
     <title>Options</title>
 

man/systemd.scope.xml

@@ -72,6 +72,10 @@
     url="http://www.freedesktop.org/wiki/Software/systemd/ControlGroupInterface/">New
     Control Group Interfaces</ulink> for an introduction on how to make
     use of scope units from programs.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Automatic Dependencies</title>
 
     <para>Unless <varname>DefaultDependencies=false</varname>
     is used, scope units will implicitly have dependencies of
@@ -82,6 +86,11 @@
     shutdown. Only scope units involved with early boot or
     late system shutdown should disable this option.
     </para>
+
+    <para>Additional implicit dependencies may be added as result of
+    resource control parameters as documented in
+    <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+
   </refsect1>
 
   <refsect1>

man/systemd.service.xml

@@ -1,4 +1,4 @@
-<?xml version='1.0'?> <!--*-nxml-*-->
+<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
 
@@ -77,18 +77,6 @@
     which configure resource control settings for the processes of the
     service.</para>
 
-    <para>Unless <varname>DefaultDependencies=</varname> is set to
-    <option>false</option>, service units will implicitly have
-    dependencies of type <varname>Requires=</varname> and
-    <varname>After=</varname> on <filename>basic.target</filename> as
-    well as dependencies of type <varname>Conflicts=</varname> and
-    <varname>Before=</varname> on
-    <filename>shutdown.target</filename>. These ensure that normal
-    service units pull in basic system initialization, and are
-    terminated cleanly prior to system shutdown. Only services
-    involved with early boot or late system shutdown should disable
-    this option.</para>
-
     <para>If a service is requested under a certain name but no unit
     configuration file is found, systemd looks for a SysV init script
     by the same name (with the <filename>.service</filename> suffix
@@ -97,8 +85,39 @@
     compatibility is quite comprehensive but not 100%. For details
     about the incompatibilities, see the <ulink
     url="http://www.freedesktop.org/wiki/Software/systemd/Incompatibilities">Incompatibilities
-    with SysV</ulink> document.
+    with SysV</ulink> document.</para>
-    </para>
+  </refsect1>
+
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>Services with <varname>Type=dbus</varname> set automatically
+    acquire dependencies of type <varname>Requires=</varname> and
+    <varname>After=</varname> on
+    <filename>dbus.socket</filename>.</para>
+
+    <para>Socket activated service are automatically ordered after
+    their activated <filename>.socket</filename> units via an
+    automatic <varname>After=</varname> dependency.</para>
+
+    <para>Unless <varname>DefaultDependencies=</varname> is set to
+    <option>false</option>, service units will implicitly have
+    dependencies of type <varname>Requires=</varname> and
+    <varname>After=</varname> on <filename>sysinit.target</filename>,
+    a dependency of type <varname>After=</varname> on
+    <filename>basic.target</filename> as well as dependencies of
+    type <varname>Conflicts=</varname> and <varname>Before=</varname>
+    on <filename>shutdown.target</filename>. These ensure that normal
+    service units pull in basic system initialization, and are
+    terminated cleanly prior to system shutdown. Only services
+    involved with early boot or late system shutdown should disable
+    this option.</para>
+
+    <para>Additional implicit dependencies may be added as result of
+    execution and resource control parameters as documented in
+    <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+    and
+    <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
   </refsect1>
 
   <refsect1>

man/systemd.slice.xml

@@ -97,6 +97,14 @@
     url="http://www.freedesktop.org/wiki/Software/systemd/ControlGroupInterface/">New
     Control Group Interfaces</ulink> for an introduction on how to make
     use of slice units from programs.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>Slice units automatically gain dependencies of type
+    <varname>After=</varname> and <varname>Requires=</varname> on
+    their immediate parent slice unit.</para>
 
     <para>Unless <varname>DefaultDependencies=false</varname>
     is used, slice units will implicitly have dependencies of

man/systemd.socket.xml

@@ -133,6 +133,40 @@
     service file).</para>
   </refsect1>
 
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>Socket units automatically gain a <varname>Before=</varname>
+    dependency on the service units they activate.</para>
+
+    <para>Socket units referring to file system paths (such as AF_UNIX
+    sockets or FIFOs) implicitly gain <varname>Requires=</varname> and
+    <varname>After=</varname> dependencies on all mount units
+    necessary to access those paths.</para>
+
+    <para>Socket units using the <varname>BindToDevice=</varname>
+    setting automatically gain a <varname>BindsTo=</varname> and
+    <varname>After=</varname> dependency on the device unit
+    encapsulating the specified network interface.</para>
+
+    <para>If <varname>DefaultDependencies=yes</varname> is set (the
+    default), socket units automatically gain a
+    <varname>Before=</varname> dependency on
+    <filename>sockets.target</filename>. They also gain a pair of
+    <varname>After=</varname> and <varname>Requires=</varname>
+    dependency on <filename>sysinit.target</filename>, and a pair of
+    <varname>Before=</varname> and <varname>Conflicts=</varname>
+    dependencies on <filename>shutdown.target</filename>. These
+    dependencies ensure that the socket unit is started before normal
+    services at boot, and is stopped on shutdown.</para>
+
+    <para>Additional implicit dependencies may be added as result of
+    execution and resource control parameters as documented in
+    <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+    and
+    <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+  </refsect1>
+
   <refsect1>
     <title>Options</title>
 
@@ -309,12 +343,14 @@
         <listitem><para>Specifies a network interface name to bind
         this socket to. If set, traffic will only be accepted from the
         specified network interfaces. This controls the
-        SO_BINDTODEVICE socket option (see
+        SO_BINDTODEVICE socket option (see <citerefentry
-        <citerefentry project='man-pages'><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+        project='man-pages'><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
         for details). If this option is used, an automatic dependency
         from this socket unit on the network interface device unit
         (<citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>
-        is created.</para></listitem>
+        is created. Note that setting this parameter might result in
+        additional dependencies to be added to the unit (see
+        above).</para></listitem>
       </varlistentry>
 
       <varlistentry>
@@ -719,7 +755,9 @@
         with <varname>Accept=no</varname>. It defaults to the service
         that bears the same name as the socket (with the suffix
         replaced). In most cases, it should not be necessary to use
-        this option.</para></listitem>
+        this option. Note that setting this parameter might result in
+        additional dependencies to be added to the unit (see
+        above).</para></listitem>
       </varlistentry>
 
       <varlistentry>

man/systemd.swap.xml

@@ -68,14 +68,15 @@
 
     <para>Additional options are listed in
     <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
-    which define the execution environment the
+    which define the execution environment the <citerefentry
-    <citerefentry project='man-pages'><refentrytitle>swapon</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+    project='man-pages'><refentrytitle>swapon</refentrytitle><manvolnum>8</manvolnum></citerefentry>
-    binary is executed in, and in
+    binary is executed in, in
     <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
-    which define the way the processes are terminated, and in
+    which define the way the these processes are
+    terminated, and in
     <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
-    which configure resource control settings for the processes of the
+    which configure resource control settings for these processes of the
-    service.</para>
+    unit.</para>
 
     <para>Swap units must be named after the devices
     or files they control. Example: the swap device
@@ -84,15 +85,28 @@
     the escaping logic used to convert a file system path to a unit
     name, see
     <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+  </refsect1>
 
-    <para>All swap units automatically get the appropriate
+  <refsect1>
-    dependencies on the devices or on the mount points of the files
+    <title>Automatic Dependencies</title>
+
+    <para>All swap units automatically get the
+    <varname>BindsTo=</varname> and <varname>After=</varname>
+    dependencies on the device units or the mount units of the files
     they are activated from.</para>
 
     <para>Swap units with <varname>DefaultDependencies=</varname>
-    enabled implicitly acquire a conflicting dependency to
+    enabled implicitly acquire a <varname>Conflicts=</varname> and an
+    <varname>After=</varname> dependency on
     <filename>umount.target</filename> so that they are deactivated at
-    shutdown.</para>
+    shutdown, unless <varname>DefaultDependencies=no</varname> is
+    specified.</para>
+
+    <para>Additional implicit dependencies may be added as result of
+    execution and resource control parameters as documented in
+    <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+    and
+    <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
   </refsect1>
 
   <refsect1>

man/systemd.target.xml

@@ -77,15 +77,20 @@
     See
     <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>
     for details).</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Automatic Dependencies</title>
 
     <para>Unless <varname>DefaultDependencies=</varname> is set to
-    <option>false</option>, target units will implicitly complement
+    <option>no</option>, target units will implicitly complement all
-    all configured dependencies of type <varname>Wants=</varname>,
+    configured dependencies of type <varname>Wants=</varname>,
     <varname>Requires=</varname>,
     <varname>RequiresOverridable=</varname> with dependencies of type
-    <varname>After=</varname> if the units in question also have
+    <varname>After=</varname>, unless an ordering dependency of any
-    <varname>DefaultDependencies=true</varname>.
+    kind between the target and the respective other unit is already
-    </para>
+    in place. Note that this behaviour is disabled if either unit has
+    <varname>DefaultDependencies=no</varname>.</para>
   </refsect1>
 
   <refsect1>

man/systemd.timer.xml

@@ -1,4 +1,4 @@
-<?xml version='1.0'?> <!--*-nxml-*-->
+<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
 
@@ -73,19 +73,29 @@
     <filename>foo.timer</filename> activates a matching service
     <filename>foo.service</filename>. The unit to activate may be
     controlled by <varname>Unit=</varname> (see below).</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>Timer units automatically gain a <varname>Before=</varname>
+    dependency on the service they are supposed to activate.</para>
 
     <para>Unless <varname>DefaultDependencies=</varname> is set to
     <option>false</option>, all timer units will implicitly have
-    dependencies of type <varname>Conflicts=</varname> and
+    dependencies of type <varname>Requires=</varname> and
-    <varname>Before=</varname> on <filename>shutdown.target</filename>
+    <varname>After=</varname> on <filename>sysinit.target</filename>,
-    to ensure that they are stopped cleanly prior to system shutdown.
+    a dependency of type <varname>Before=</varname> on
-    Timer units with at least one <varname>OnCalendar=</varname>
+    <filename>timers.target</filename>, as well as
-    directive will have an additional <varname>After=</varname>
+    <varname>Conflicts=</varname> and <varname>Before=</varname> on
-    dependency on <filename>timer-sync.target</filename> to avoid
+    <filename>shutdown.target</filename> to ensure that they are
-    being started before the system clock has been correctly set. Only
+    stopped cleanly prior to system shutdown.  Timer units with at
-    timer units involved with early boot or late system shutdown
+    least one <varname>OnCalendar=</varname> directive will have an
-    should disable the <varname>DefaultDependencies=</varname>
+    additional <varname>After=</varname> dependency on
-    option.</para>
+    <filename>timer-sync.target</filename> to avoid being started
+    before the system clock has been correctly set. Only timer units
+    involved with early boot or late system shutdown should disable
+    the <varname>DefaultDependencies=</varname> option.</para>
   </refsect1>
 
   <refsect1>

man/systemd.unit.xml

@@ -1,4 +1,4 @@
-<?xml version='1.0'?> <!--*-nxml-*-->
+<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
 <!ENTITY % entities SYSTEM "custom-entities.ent" >
@@ -195,12 +195,6 @@
          consider it mostly obsolete, and want people to
          use .d/ drop-ins instead. -->
 
-    <para>Note that while systemd offers a flexible dependency system
-    between units it is recommended to use this functionality only
-    sparingly and instead rely on techniques such as bus-based or
-    socket-based activation which make dependencies implicit,
-    resulting in a both simpler and more flexible system.</para>
-
     <para>Some unit names reflect paths existing in the file system
     namespace. Example: a device unit
     <filename>dev-sda.device</filename> refers to a device with the
@@ -253,6 +247,31 @@
 
   </refsect1>
 
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>Note that while systemd offers a flexible dependency system
+    between units it is recommended to use this functionality only
+    sparingly and instead rely on techniques such as bus-based or
+    socket-based activation which make dependencies implicit,
+    resulting in a both simpler and more flexible system.</para>
+
+    <para>A number of unit dependencies are automatically established,
+    depending on unit configuration. On top of that, for units with
+    <varname>DefaultDependencies=yes</varname> (the default) a couple
+    of additional dependencies are added. The precise effect of
+    <varname>DefaultDependencies=yes</varname> depends on the unit
+    type (see below).</para>
+
+    <para>If <varname>DefaultDependencies=yes</varname> is set, units
+    that are referenced by other units of type
+    <filename>.target</filename> via a <varname>Wants=</varname> or
+    <varname>Requires=</varname> dependency might automatically gain
+    an <varname>Before=</varname> dependency too. See
+    <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+    for details.</para>
+  </refsect1>
+
   <refsect1>
     <title>Unit File Load Path</title>