nilrt-net-boot: NI Linux RT Network Boot Tools

Network booting is the process of booting a computer system from a network rather than local disk/flash media. The system's kernel and file systems are retrieved over the network by firmware/BIOS instead of accessing those files from local storage. In many cases, storage devices can be completely removed from these systems to reduce cost. These schemes are typically employed to centralize software and system configuration to reduce maintenance overhead.

Preboot Execution Environment (PXE) is a common protocol to implement network boot. It's supported on some NI controllers like PXIe-8840. The tutorial below demonstrates PXE network booting an NI Linux RT OS with user installed software (E.g. LabVIEW RT built app) on PXI.

Written by Haris Okanovic [email protected] to demonstrate network boot capabilities of NI Linux RT. Use at your own risk.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Create ramdisk image

1. Format, install software, and otherwise configure a real (hardware) controller using MAX, SD, LabVIEW, and/or other tools. This will serve as a template system to take an image.

2. Reboot to safemode

3. Copy the enclosed nilrt-make-netboot-image.sh to admin's home directory via ssh/sftp.

4. Run nilrt-make-netboot-image.sh -i /mnt/userfs -o /path/to/img.d as admin to take an image. Substitute /path/to/img.d with any secondary storage device that's big enough to store the image. E.g. This could be a USB mass storage device or a network share.

5. Copy img.d into the enclosed tftpboot directory on your desktop. This directory contains other files needed for PXE boot. The layout is documented below for reference.

TFTP Root Directory Layout

The tftpboot directory should look like this after img.d is copied:

tftpboot/
    img.d/
        bzImage - Linux kernel image
        init - gzipped cpio ramdisk of runmode filesystem
        SHA256SUM - checksums of aforementioned files
    pxelinux.cfg/
        default - PXE configuration file tuned for NI Linux RT
    pxelinux.0 - x86_64 Syslinux PXE boot loader (binary)
    ldlinux.c32 - x86_64 Syslinux PXE boot loader (binary)

NOTE: You can compile your own Syslinux PXE boot loader if desired.

Syslinux PXE Documentation: https://wiki.syslinux.org/wiki/index.php?title=PXELINUX

Syslinux Source: https://mirrors.edge.kernel.org/pub/linux/utils/boot/syslinux/

PXE Image Hosting Example

NOTE: This simple example uses dnsmasq to provide DHCP and TFTP services on an isolated network, directly connected to hardware we're booting. This configuration is intended only to demonstrate PXE booting capabilities in the simplest environment possible. Please take care when adapting this example for your network. Hosting a second DHCP service may create problems for other users/devices on your network!

1. Connect a PXE capable NI controller (E.g. PXIe-8840) to an unused Ethernet adapter on your desktop. We'll call that adapter "demoEth". You can connect a USB Ethernet adapter if you don't have a second one to work with.

2. Run sudo ifconfig demoEth 192.168.92.1/24 to give demoEth a static address on the new network. You can change the 192.168.92.X subnet if it's already in use. Be sure to update dnsmasq.conf accordingly.

3. Run dnsmasq --no-daemon --conf-file=dnsmasq.conf --tftp-root="$PWD/tftpboot" --interface=demoEth to launch DHCP and TFTP services.

4. Boot the NI controller to BIOS by repeatedly pressing DEL after powering on.

5. Go to the "Boot" tab. Enable the "PXE Network Boot" option. Disable all "Boot Option ##"'s, except the network adapter.

6. Save and reboot in BIOS: Go to "Save & Exit" tab then click on "Save Changes and Reset" option.

7. You should see the PXE boot agent run, download several files via TFTP, and boot into NI Linux RT. It will retry indefinitely if DHCP and TFTP are not configured correctly and you did not specify a fallback boot device in BIOS.