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Unofficial NanoBSD technical resources

Externals links about NanoBSD

Here are a list of docs and tutorials about NanoBSD:

Understanding NanoBSD

What is NanoBSD ?

It's a shell script (/usr/src/tools/tools/nanobsd/) that generate embedded FreeBSD image disk.

Images generated by NanoBSD

After using NanoBSD, you will found a full disk image (_.disk.full) that contains 2 partitions (p1 and p2) (both copy of _.disk.image file). The file _.disk.image is the light FreeBSD filesystem (in diskless mode). Using 2 partitions permit to use a simple and safe upgrading process: The new _.disk.image file is copied over the non-active partition, and the bootloader is modified for boot on the non-active partition at the next boot. There are the scripts updatep1 and updatep2 for this task.

Using NanoBSD

NanoBSD manage flash device and prevent fsck by mounting the filesystem read-only. For saving configuration file, you need to copy /etc into /conf: There is the script save_cfg for this task.

Studying NanoBSD

Command options

Here are the command line options of NanoBSD:

Usage: $0 [-bikqvw] [-c config_file]
  -b      suppress builds (both kernel and world)
  -i      suppress disk image build
  -k      suppress buildkernel
  -n      add -DNO_CLEAN to buildworld, buildkernel, etc
  -q      make output more quite
  -v      make output more verbose
  -w      suppress buildworld
  -c      specify config file
  -h      Display usage information.


Here are the functions steps:

  1. clean_build
  2. make_conf_build
  3. build_world
  4. build_kernel
  5. clean_world
  6. make_conf_install
  7. install_world
  8. install_etc
  9. setup_nanobsd_etc
  10. install_kernel
  11. run_customize
  12. setup_nanobsd
  13. prune_usr
  14. run_late_customize
  15. create_${NANO_ARCH}_diskimage
  16. last_orders

Variables Table


Name Value (in BSDRP) Description
CONF_BUILD Options to put in make.conf during buildworld only
CONF_WORLD A big list of WITHOUT_ Options to put in make.conf during both build- & installworld
CONF_INSTALL A big list of WITHOUT_ too Options to put in make.conf during installworld only
MAKEOBJDIRPREFIX /usr/obj/nanobsd.BSDRP.{ARCH} object directory
NANO_ARCH i386/amd Target architecture
NANO_BOOT0CFG -o packet -s 1 -m 3 Boot0cfg configuration mode
NANO_CONFSIZE 2048 Size of configuration file system in 512 bytes sectors
NANO_CUSTOMIZE Customize commands
NANO_DATASIZE 2048 Size of data file system in 512 bytes sectors
NANO_DISKIMGDIR /usr/obj/nanobsd.BSDRP.{ARCH} The directory to put the final images
NANO_DRIVE ad0 (TO ADD in BSDRP make!) The drive name of the media at runtime
NANO_GLABEL_SYS BSDRP glabel name for system partition
NANO_GLABEL_CFG cfg glabel name for configuration partition
NANO_GLABEL_DATA data glabel name for data partition
NANO_IMAGES 2 Number of code images on media (1 or 2)
NANO_IMGNAME BSDRP.img The default name for any image we create
NANO_INIT_IMG2 What to do with the second image partition: 0 (empty), 1 (copy twice the image)
NANO_KERNEL BSDRP-I386 / BSDRP-AMD64 Name of the kernel config file
NANO_LATE_CUSTOMIZE Late customize commands
NANO_MAKE_CONF_INSTALL /usr/obj/nanobsd.BSDRP.{ARCH}/make.conf.install
NANO_MD_BACKING file Backing type of md(4) device (file or swap)
NANO_MEDIASIZE 1200000 Target media size in 512 bytes sectors
NANO_NAME BSDRP Name of the obj dir
NANO_NEWFS -b 4096 -f 512 -i 8192 -O1 -m 2 -U Newfs paramters to use
NANO_OBJ /usr/obj/nanobsd.BSDRP.{ARCH} Object tree directory
NANO_PACKAGE_DIR /usr/src/tools/tools/nanobsd/BSDRP/Pkg Where cust_pkg() finds packages to install
NANO_PMAKE make -j 3 Parallel Make
NANO_RAM_ETCSIZE 10204 Size of the /etc ramdisk in 512 bytes sectors
NANO_RAM_TMPVARSIZE 20480 Size of the /tmp+/var ramdisk in 512 bytes sectors
NANO_SRC /usr/src Source tree directory
NANO_TOOLS tools/tools/nanobsd/BSDRP Where nanobsd additional files live under the source tree
NANO_WORLDDIR /usr/obj/nanobsd.BSDRP.{ARCH}/_.w Target World directory

Functions Table


Name Description
build_kernel Copy kernel config file and Build Kernel
build_world Run Build World
clean_build Delete and create object directory
clean_world Clean and create object directory
cust_install_files Copy all files under Files to nanobsd target
FlashDevice Load FlashDevice.sub
install_world Install all binary (make installworld)
install_etc Install /etc (make distribution
install_kernel Install kernel (make installkernel)
make_conf_build Construct build make.conf using $CONF_WORLD and $CONF_BUILD
make_conf_install Construct install make.conf using $CONF_WORLD and $CONF_BUILD
prune_usr Remove all empty directories in target /usr
run_customize run customize scripts (commands in $NANO_CUSTOMIZE)
run_late_customize run late customize scripts (commands in $NANO_LATE_CUSTOMIZE and cust_ functions)
setup_nanobsd configure nanobsd setup: Move /usr/local/etc to /etc/local
setup_nanobsd_etc configure target nanobsd /etc: enable diskless, enable r/o of /, create fstab
UsbDevice USB device geometries
create_${NANO_ARCH}_diskimage Build disk image (partition, format, bootloader, etc.)
last_orders Empty function to be customized by user (ex: copy diskimage to other place)

NanoBSD logs files

Name Description
_.bk Build Kernel log Build World log
_.di Disk image creation log
_.dl nanobsd setup creation log (/etc, /conf, etc..)
_.du nanobsd disk usage (du) output
_.env All environnement used during nanobsd runs
_.etc Install etc log
_.fdisk File used for fdisk the nanoBSD image
_.ik Install kernel log files
_.iw Install world log files
_.mtree Light mtree file of the nanoBSD image

BSDRP patches for NanoBSD

Port compiling patches

This patches is an improvement of the method used by Gitoyen NanoBSD router.

It replaces the installation of package by compiling ports during NanoBSD image build: This permit to add ports during build process of NanoBSD images.

This patch support cross-compilation i386 ports from an amd64 release.

You can found this patches as the function add_port () in the BSDRP nano configuration file.

But the best solution should to use poudriere to generate packages.

documentation/technical_docs/nanobsd.txt · Last modified: 2021/01/18 16:03 by olivier