Introduction to NanoBSD

2.3.1 Configuration options

With configuration settings, it is possible to configure options passed to both the buildworld and installworld stages of the NanoBSD build process, as well as internal options passed to the main build process of NanoBSD. Through these options it is possible to cut the system down, so it will fit on as little as 64MB. You can use the configuration options to trim down FreeBSD even more, until it will consists of just the kernel and two or three files in the userland.

The configuration file consists of configuration options, which override the default values. The most important directives are:

• NANO_NAME — Name of build (used to construct the workdir names).

• NANO_SRC — Path to the source tree used to build the image.

• NANO_KERNEL — Name of kernel configuration file used to build kernel.

• CONF_BUILD — Options passed to the buildworld stage of the build.

• CONF_INSTALL — Options passed to the installworld stage of the build.

• CONF_WORLD — Options passed to both the buildworld and the installworld stage of the build.

• FlashDevice — Defines what type of media to use. Check the FlashDevice.sub file for more details.

2.3.2 Custom functions

It is possible to fine-tune NanoBSD using shell functions in the configuration file. The following example illustrates the basic model of custom functions:

cust_foo () (
	echo "bar=baz" > \
		${NANO_WORLDDIR}/etc/foo
)
customize_cmd cust_foo

A more useful example of a customization function is the following, which changes the default size of the /etc directory from 5MB to 30MB:

cust_etc_size () (
	cd ${NANO_WORLDDIR}/conf
	echo 30000 > default/etc/md_size
)
customize_cmd cust_etc_size

There are a few default pre-defined customization functions ready for use:

• cust_comconsole — Disables getty(8) on the VGA devices (the /dev/ttyv* device nodes) and enables the use of the COM1 serial port as the system console.

• cust_allow_ssh_root — Allow root to login via sshd(8).

• cust_install_files — Installs files from the nanobsd/Files directory, which contains some useful scripts for system administration.

2.3.3 Adding packages

Packages can be added to a NanoBSD image using a custom function. The following function will install all the packages located in /usr/src/tools/tools/nanobsd/packages:

install_packages () (
mkdir -p ${NANO_WORLDDIR}/packages
cp /usr/src/tools/tools/nanobsd/packages/* ${NANO_WORLDDIR}/packages
chroot ${NANO_WORLDDIR} sh -c 'cd packages; pkg_add -v *;cd ..;'
rm -rf ${NANO_WORLDDIR}/packages
)
customize_cmd install_packages

2.3.4 Configuration file example

A complete example of a configuration file for building a custom NanoBSD image can be:

NANO_NAME=custom
NANO_SRC=/usr/src
NANO_KERNEL=MYKERNEL
NANO_IMAGES=2

CONF_BUILD='
NO_KLDLOAD=YES
NO_NETGRAPH=YES
NO_PAM=YES
'

CONF_INSTALL='
NO_ACPI=YES
NO_BLUETOOTH=YES
NO_CVS=YES
NO_FORTRAN=YES
NO_HTML=YES
NO_LPR=YES
NO_MAN=YES
NO_SENDMAIL=YES
NO_SHAREDOCS=YES
NO_EXAMPLES=YES
NO_INSTALLLIB=YES
NO_CALENDAR=YES
NO_MISC=YES
NO_SHARE=YES
'

CONF_WORLD='
NO_BIND=YES
NO_MODULES=YES
NO_KERBEROS=YES
NO_GAMES=YES
NO_RESCUE=YES
NO_LOCALES=YES
NO_SYSCONS=YES
NO_INFO=YES
'

FlashDevice SanDisk 1G

cust_nobeastie() (
	touch ${NANO_WORLDDIR}/boot/loader.conf
	echo "beastie_disable=\"YES\"" >> ${NANO_WORLDDIR}/boot/loader.conf
)

customize_cmd cust_comconsole
customize_cmd cust_install_files
customize_cmd cust_allow_ssh_root
customize_cmd cust_nobeastie

2.4.1 Using ftp(1)

If the transfer speed is in first place, use this example:

# ftp myhost
get _.disk.image "| sh updatep1"

2.4.2 Using ssh(1)

If a secure transfer is preferred, consider using this example:

# ssh myhost cat _.disk.image.gz | zcat | sh updatep1

2.4.3 Using nc(1)

Try this example if the remote host is not running neither ftpd(8) or sshd(8) service: