Add documentation for autofs(5).

Reviewed by:	gjb@
Approved by:	gjb@
Sponsored by:	The FreeBSD Foundation

en_US.ISO8859-1/books/handbook/network-servers/chapter.xml

@@ -797,7 +797,7 @@ rpc_statd_enable="YES"</programlisting>
 
     <sect2 xml:id="network-amd">
       <info>
-      <title>Automating Mounts</title>
+      <title>Automating Mounts With &man.amd.8;</title>
 
 	<authorgroup>
 	  <author>
@@ -897,6 +897,113 @@ Exports list on foobar:
       <para>Consult &man.amd.8; and &man.amd.conf.5; for more
 	information.</para>
     </sect2>
+
+    <sect2 xml:id="network-autofs">
+      <title>Automating Mounts with &man.autofs.5;</title>
+
+      <note>
+	<para>The &man.autofs.5; automount facility is supported
+	  starting with &os;&nbsp;10.1-RELEASE.  To use the
+	  automounter functionality in older versions of &os;, use
+	  &man.amd.8; instead.  This chapter only describes the
+	  &man.autofs.5; automounter.</para>
+      </note>
+
+
+      <indexterm><primary>autofs</primary></indexterm>
+      <indexterm>
+	<primary>automounter subsystem</primary>
+      </indexterm>
+
+      <para>The &man.autofs.5; facility is a common name for several
+	components that, together, allow for automatic mounting of
+	remote and local filesystems whenever a file or directory
+	within that file system is accessed.  It consists of the
+	kernel component, &man.autofs.5;, and several userspace
+	applications: &man.automount.8;, &man.automountd.8; and
+	&man.autounmountd.8;.  It serves as an alternative for
+	&man.amd.8; from previous &os; releases.  Amd is still
+	provided for backward compatibility purposes, as the two use
+	different map format; the one used by autofs is the same as
+	with other SVR4 automounters, such as the ones in Solaris,
+	MacOS X, and Linux.</para>
+
+      <para>The &man.autofs.5; source is mounted on specified
+	mountpoints by &man.automount.8;, usually invoked during
+	boot.</para>
+
+      <para>Whenever a process attempts to access file within the
+	&man.autofs.5; mountpoint, the kernel will notify
+	&man.automountd.8; daemon and pause the triggering process.
+	The &man.automountd.8; daemon will handle kernel requests by
+	finding the proper map and mounting the filesystem according
+	to it, then signal the kernel to release blocked process.  The
+	&man.autounmountd.8; daemon automatically unmounts automounted
+	filesystems after some time, unless they are still being
+	used.</para>
+
+      <para>The primary autofs configuration file is
+	<filename>/etc/auto_master</filename>.  It assigns individual
+	maps to top-level mounts.  For an explanation of
+	<filename>auto_master</filename> and the map syntax, refer to
+	&man.auto.master.5;.</para>
+
+      <para>There is a special automounter map mounted on
+	<filename>/net</filename>.  When a file is accessed within
+	this directory, &man.autofs.5; looks up the corresponding
+	remote mount and automatically mounts it.  For instance, an
+	attempt to access a file within
+	<filename>/net/foobar/usr</filename> would tell
+	&man.automountd.8; to mount the <filename
+	  class="directory">/usr</filename> export from the host
+	<systemitem class="fqdomainname">foobar</systemitem>.</para>
+
+      <example>
+	<title>Mounting an Export With &man.autofs.5;</title>
+
+	<para>In this example, <command>showmount -e</command> shows
+	  the exported file systems that can be mounted from the
+	  <acronym>NFS</acronym> server,
+	  <systemitem class="fqdomainname">foobar</systemitem>:</para>
+
+	<screen>&prompt.user; <userinput>showmount -e foobar</userinput>
+Exports list on foobar:
+/usr                               10.10.10.0
+/a                                 10.10.10.0
+&prompt.user; <userinput>cd /host/foobar/usr</userinput></screen>
+      </example>
+
+      <para>The output from <command>showmount</command> shows
+	<filename class="directory">/usr</filename> as an export.
+	When changing directories to <filename
+	  class="directory">/host/foobar/usr</filename>,
+	&man.automountd.8; intercepts the request and attempts to
+	resolve the hostname <systemitem
+	  class="fqdomainname">foobar</systemitem>.  If successful,
+	&man.automountd.8; automatically mounts the source
+	export.</para>
+
+      <para>To enable &man.autofs.5; at boot time, add this line to
+	<filename>/etc/rc.conf</filename>:</para>
+
+      <programlisting>autofs_enable="YES"</programlisting>
+
+      <para>Then &man.autofs.5; can be started by running:</para>
+
+      <screen>&prompt.root; <userinput>service automount start</userinput></screen>
+      <screen>&prompt.root; <userinput>service automountd start</userinput></screen>
+      <screen>&prompt.root; <userinput>service autounmountd start</userinput></screen>
+
+      <para>The &man.autofs.5; map format is the same as in other
+	operating systems, it might be desirable to consult
+	information from other operating systems, such as the <link
+	  xlink:href="http://images.apple.com/business/docs/Autofs.pdf">Mac
+	  OS X document</link>.</para>
+
+      <para>Consult the &man.automount.8;, &man.automountd.8;,
+      &man.autounmountd.8;, and &man.auto.master.5; manual pages for
+      more information.</para>
+    </sect2>
   </sect1>
 
   <sect1 xml:id="network-nis">