3.12. Advanced Installation Guide
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## 3.12. Advanced Installation Guide

Contributed by Valentino Vaschetto.
Updated by Marc Fonvieille.

This section describes how to install FreeBSD in exceptional cases.

### 3.12.1. Installing FreeBSD on a System Without a Monitor or Keyboard

This type of installation is called a “headless install” because the machine to be installed does not have either an attached monitor or a VGA output. This type of installation is possible using a serial console, another machine which acts as the main display and keyboard. To do this, follow the steps to create an installation USB stick, explained in Section 3.3.7, “Prepare the Boot Media”, or download the correct installation ISO image as described in Section 3.13.1, “Creating an Installation ISO”.

To modify the installation media to boot into a serial console, follow these steps. If using a CD/DVD media, skip the first step):

1. Enabling the Installation USB Stick to Boot into a Serial Console

   By default, booting into the USB stick boots into the installer. To instead boot into a serial console, mount the USB disk onto a FreeBSD system using mount(8):

   `#` `mount /dev/`da0a` `/mnt``

   ### Note:

   Adapt the device node and the mount point to the situation.

   Once the USB stick is mounted, set it to boot into a serial console. Add this line to `/boot/loader.conf` on the USB stick:

   `#` `echo 'console="comconsole"' >> `/mnt`/boot/loader.conf`

   Now that the USB is stick configured correctly, unmount the disk using umount(8):

   `#` `umount `/mnt``

   Now, unplug the USB stick and jump directly to the third step of this procedure.

2. Enabling the Installation CD/DVD to Boot into a Serial Console

   By default, when booting into the installation CD/DVD, FreeBSD boots into its normal install mode. To instead boot into a serial console, extract, modify, and regenerate the ISO image before burning it to the CD/DVD media.

   From the FreeBSD system with the saved installation ISO image, use tar(1) to extract all the files:

   `#` `mkdir `/path/to/headless-iso`` `#` `tar -C `/path/to/headless-iso` -pxvf FreeBSD-`9.1`-RELEASE-`i386`-disc1.iso`

   Next, set the installation media to boot into a serial console. Add this line to the `/boot/loader.conf` of the extracted ISO image:

   `#` `echo 'console="comconsole"' >> `/path/to/headless-iso`/boot/loader.conf`

   Then, create a new ISO image from the modified tree. This example uses mkisofs(8) from the `sysutils/cdrtools` package or port:

   `#` `mkisofs -v -b boot/cdboot -no-emul-boot -r -J -V "`Headless_install`" \ -o `Headless-`FreeBSD-`8.4`-RELEASE-`i386`-disc1.iso`/path/to/headless-iso``

   Now that the ISO image is configured correctly, burn it to a CD/DVD media using a burning application.

3. Connecting the Null-modem Cable

   Connect a null-modem cable to the serial ports of the two machines. A normal serial cable will not work. A null-modem cable is required.

4. Booting Up for the Install

   It is now time to go ahead and start the install. Plug in the USB stick or insert the CD/DVD media in the headless install machine and power it on.

5. Connecting to the Headless Machine

   Next, connect to that machine with cu(1):

   `#` `cu -l /dev/cuau0`

The headless machine can now be controlled using cu(1). It will load the kernel and then dispaly a selection of which type of terminal to use. Select the FreeBSD color console and proceed with the installation.

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