Date: Tue, 15 Oct 2002 21:58:49 +0200 From: Udo Erdelhoff <ue@nathan.ruhr.de> To: freebsd-doc@freebsd.org Subject: Please review: new handbook chapter on serial install Message-ID: <20021015195849.GA76747@nathan.internal>
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Hi,
the chapter about using a serial console lacks one important feature:
A description how to install FreeBSD with a serial console. As I had
to re-install one of my boxes today anyway, I recorded what needs to
be done and turned it into sgml. Here's the result:
Index: chapter.sgml
===================================================================
RCS file: /home/ncvs/doc/en_US.ISO8859-1/books/handbook/serialcomms/chapter.sgml,v
retrieving revision 1.66
diff -u -r1.66 chapter.sgml
--- chapter.sgml 30 Sep 2002 15:33:26 -0000 1.66
+++ chapter.sgml 15 Oct 2002 19:47:57 -0000
@@ -2609,6 +2609,135 @@
attach a monitor into it. You might also try installing an AMI
BIOS.</para>
</sect2>
+
+ <sect2 id="serialconsole-install">
+ <sect2info>
+ <author>
+ <firstname>Udo</firstname>
+ <surname>Erdelhoff</surname>
+ <contrib>Contributed by </contrib>
+ </author>
+ </sect2info>
+
+ <title>Using a Serial Console to Install FreeBSD</title>
+
+ <para>With only a little bit of work, it is also possible to
+ <emphasis>install</emphasis> a FreeBSD system over a serial
+ console. Of course, you will have to prepare your BIOS first
+ to be able to boot without a keyboard (or even without a
+ graphics adapter). You will have to configure it to try to
+ boot from floppy before it tries to boot from hard disk. This
+ cannot be done over a serial console on most PC
+ mainboards.</para>
+
+ <para>The secret of installing FreeBSD over a serial console is
+ the fact that even the boot loader and the kernel used on the
+ installation floppies support a serial console, just like
+ their big counterparts that are installed on your hard disk.
+ In other words, all you have to do is to create a
+ <filename>boot.config</filename> file on the boot medium. In
+ theory, this could be a remotely mounted root file system for
+ a diskless installation, a modified installation CD/DVD, or a
+ modified boot floppy. The easiest solution (and the only one
+ described in this chapter) is to create a modified boot floppy
+ because this can be done with the on-board tools of a standard
+ installation. Please note that you do
+ <emphasis>NOT</emphasis> have to install the complete system
+ from floppy disk, you can still use your CD-ROM, DVD-ROM, or
+ your internet connection to get the distributions.</para>
+
+
+ <para>The official way of creating a modified boot floppy is to
+ modify the scripts and <filename>Makefile</filename> used by
+ <command>make release</command>. This is not required if the
+ only change is the addition of a
+ <filename>boot.config</filename> file on the boot disk. The
+ boot disk consists of two parts, the boot sector/loader and
+ the installation kernel. The latter is stored in a small UFS
+ file system that can be modified and manipulated with all the
+ usual tools. This includes the creation of
+ <filename>boot.config</filename>. All you need is a system
+ that can mount, read, and write FreeBSD file systems. As a
+ rule of thumb, this means another FreeBSD system. Once you
+ have this, it is rather easy to create a modified
+ <filename>boot.flp</filename> for installation over a serial
+ console.</para>
+
+ <procedure>
+ <step>
+ <para>Create floppy disks from the
+ <filename>kern.flp</filename> and
+ <filename>mfsroot.flp</filename> images.</para>
+ </step>
+
+ <step>
+ <para>Insert the floppy disk with the
+ <filename>kern.flp</filename> into the drive.</para>
+ </step>
+
+ <step>
+ <para>Mount the file system on
+ <filename>kern.flp</filename>, create a sutitable
+ <filename>boot.config</filename>, and unmount the
+ disk.</para>
+
+ <screen>&prompt.root; <userinput>mount /dev/fd<replaceable>X</replaceable> /mnt</userinput>
+&prompt.root; <userinput>echo -P > /mnt/boot.config</userinput>
+&prompt.root; <userinput>umount /mnt</userinput></screen>
+ </step>
+
+ <step>
+ <para>Connect your serial console to the new FreeBSD system,
+ just as explained above.</para>
+ </step>
+
+ <step>
+ <para>Insert the modified <filename>kern.flp</filename> into
+ the disk drive of the new FreeBSD system and start/reboot
+ it.</para>
+ </step>
+ </procedure>
+
+ <para>After a while, you should see activity on your serial
+ console, probably the <quote>sppiner</quote>, followed by the
+ usual start messages from the kernel. With two minor
+ exceptions, you can use &man.sysinstall.8; just as if you
+ were installing FreeBSD with a conventional set-up:</para>
+
+ <itemizedlist>
+ <listitem>
+ <para>&man.sysinstall.8; cannot start the emergency
+ holographic shell on an additional VTY because there is
+ only one serial console.</para>
+ </listitem>
+
+ <listitem>
+ <para>There is an additional dialog at the start of
+ &man.sysinstall.8; where you can define which kind of
+ terminal you are using.</para>
+ </listitem>
+ </itemizedlist>
+
+ <para>Once &man.sysinstall.8; has finished extracting all the
+ distributions, it will ask you if you want to change your
+ settings. You will have to do this, because the newly
+ installed system is not configured for a serial console
+ yet. In order to allow log-ins over the serial console,
+ you will have to select <menuentry>TTYs</menuentry> from
+ the <menuentry>Configuration<menuentry>. Activate the
+ &man.getty.8; on <devicename>ttyd0</devicename> and
+ configure the terminal type to the appropriate value
+ for your terminal.</para>
+
+ <para>The second required change is the creation of a
+ <filename>boot.config</filename> file on the root file system
+ of your newly installed FreeBSD box. This can be done by
+ selecting <literal>shell</literal> from the
+ <literal>Fixit</literal> menu. Just type <command>echo -P
+ > /boot.config</command>, exit the shell, quit
+ &man.sysinstall.8; and watch your newly installed system boot
+ with an active serial console.</para>
+ </sect2>
</sect1>
</chapter>
Comments?
/s/Udo
--
Enjoy the beauty and power of root
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