Most white box switch boxes (at least the ones that ship with SONiC) has a BMC that is connected to a switch which also connects to external management and the COMex mgmt NIC.
In theory, we can run netboot COMex from BMC. netboot is quite simple, need a dhcp server (typically well known dnsmasq)
So the idea is, to boot COMex without an external media i.e. USB stick.
First we need dnsmasq to run on BMC, in my case, AST2500 running OpenBMC thus, linux-armv5 target.
dnsmasq is quite simple to cross-compile especially with dockcross
# get dockcross
docker run --rm dockcross/linux-armv5 > ./dockcross-linux-armv5
chmod +x dockcross-linux-armv5
./dockcross-linux-armv5 bash
# build dnsmasq
git clone https://github.com/imp/dnsmasq
cd dnsmasq
makeYAY! ArchLinux FTW \o/
- ✅ ArchLinux https://archlinux.org/releng/netboot/
- ✅ netboot.xyz https://boot.netboot.xyz/ipxe/netboot.xyz.efi
- ❌ Ubuntu Netboot http://archive.ubuntu.com/ubuntu/dists/bionic-updates/main/installer-amd64/current/images/netboot/netboot.tar.gz (would need an UEFI image)
Make sure to add dhcp advertised gateway to the eth0.
interface=eth0,lo
bind-interfaces
domain=my.lan
# DHCP range-leases
dhcp-range=eth0,192.168.15.5,192.168.15.253,255.255.255.0,1h
# PXE file to boot from
dhcp-boot=ipxe.efi
# For Ubuntu Netboot Options
# pxe-prompt="Press F8 for menu.", 60
# pxe-service=x86PC, "PXE boot from network server 192.168.15.1", pxelinux
# Gateway
# dhcp-option=3,192.168.15.1
# DNS
dhcp-option=6,1.1.1.1, 8.8.8.8
server=1.1.1.1
# Broadcast Address
# dhcp-option=28,10.0.0.255
# NTP Server
# dhcp-option=42,0.0.0.0
# TFTP Server
dhcp-option=66,192.168.15.1
enable-tftp
tftp-root=/var/lib/tftpboot
log-dhcp
log-queries
log-facility=/tmp/dnsmasq.log
and just run the dnsmasq with this,
kill `pidof dnsmasq`; \
dnsmasq -C dnsmasq.conf && \
tail -f /tmp/dnsmasq.log