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Zero0ne
Asked: 2022-05-05 17:35:06 +0800 CST

22.04 Jammy PXE Booting Help

  • 772

In summary, my issue specifically is when I PXE boot a UEFI system, I get stuck at a grub> prompt. It appears that the UEFI systems aren't loading the grub.cfg file and I'll be damned if I can figure out why.

Since 22.04 is no longer providing us a mini.iso or netboot.iso option, I've been building (in our lab) a POC of the 'new' way to automate deployment of systems. For the most part I've been following the instructions from these two URLs:

For now my PoC is all sitting in a small Hyper-V lab. The network config is pretty simple in that I have a pfSense FW giving my lab network access to the internet and everything behind my FW is on a closed (private) network. This allows me full control over things like DHCP and such.

On what I'm calling my PXE sever, I have installed:

  • apache2
  • isc-dhcp-server
  • tftpd-hpa

TFTP Directory structure:

├── boot
│   ├── bootx64.efi
│   ├── grub
│   │   ├── font.pf2
│   │   ├── grub.cfg
│   │   ├── unicode.pf2
│   │   └── x86_64-efi
│   │       ├── command.lst
│   │       ├── crypto.lst
│   │       ├── fs.lst
│   │       └── terminal.lst
│   ├── grubx64.efi
│   ├── jammy
│   │   ├── initrd
│   │   └── vmlinuz
│   ├── ldlinux.c32 -> ./syslinux/bios/ldlinux.c32
│   ├── libutil.c32 -> ./syslinux/bios/libutil.c32
│   ├── menu.c32 -> ./syslinux/bios/menu.c32
│   ├── pxelinux.0
│   ├── pxelinux.cfg
│   │   └── default
│   └── syslinux
│       └── bios
│           ├── ldlinux.c32
│           ├── libutil.c32
│           └── menu.c32
└── grub -> ./boot/grub/

/etc/dhcp/dhcpd.conf

allow booting;
allow bootp;
option arch code 93 = unsigned integer 16;

subnet 172.16.1.0 netmask 255.255.255.0 {
    range 172.16.1.100 172.16.1.110;
}

host test1 {
    hardware ethernet 00:15:5d:01:21:07;
    if option arch = 00:07 {
        filename "boot/bootx64.efi";
    } else {
        filename "boot/pxelinux.0";
    }
    next-server 172.16.1.50;
    fixed-address 172.16.1.60;
}

host test2 {
        hardware ethernet 00:15:5d:01:21:08;
        if option arch = 00:07 {
               filename "boot/bootx64.efi";
        } else {
                filename "boot/pxelinux.0";
        }
        next-server 172.16.1.50;
        fixed-address 172.16.1.61;
}

NOTE: I want DHCP to be issued by my pfSense server but I discovered the only way to get isc-dhcp-server to start was to specify some sort or range. I need to resolve this but for now it does seem that since everything is on the same subnet things are working well enough with this config.

/etc/default/tftpd-hpa

# /etc/default/tftpd-hpa

TFTP_USERNAME="tftp"
TFTP_DIRECTORY="/tftp"
TFTP_ADDRESS=":69"
TFTP_OPTIONS="--secure

/etc/default/isc-dhcp-server

# Defaults for isc-dhcp-server (sourced by /etc/init.d/isc-dhcp-server)

# Path to dhcpd's config file (default: /etc/dhcp/dhcpd.conf).
#DHCPDv4_CONF=/etc/dhcp/dhcpd.conf
#DHCPDv6_CONF=/etc/dhcp/dhcpd6.conf

# Path to dhcpd's PID file (default: /var/run/dhcpd.pid).
#DHCPDv4_PID=/var/run/dhcpd.pid
#DHCPDv6_PID=/var/run/dhcpd6.pid

# Additional options to start dhcpd with.
#       Don't use options -cf or -pf here; use DHCPD_CONF/ DHCPD_PID instead
#OPTIONS=""

# On what interfaces should the DHCP server (dhcpd) serve DHCP requests?
#       Separate multiple interfaces with spaces, e.g. "eth0 eth1".
INTERFACESv4="eth0"
INTERFACESv6="eth0"

/tftp/boot/grub/grub.cfg

set timeout=30

loadfont unicode

set menu_color_normal=white/black
set menu_color_highlight=black/light-gray

menuentry "Install Ubuntu Jammy (22.04)" {
        set gfxpayload=keep
        linux   /boot/jammy/vmlinuz ip=dhcp cloud-config-url=/dev/null url=http://172.16.1.50/isos/jammy/ubuntu-22.04-live-server-amd64.iso autoinstall ds="nocloud-net;s=http://172.16.1.50/cloud-init/jammy/" --- # Don't forget the slash at the end.
        initrd  /boot/jammy/initrd
}

tcpdump -n -i eth0 port 69

tcpdump: verbose output suppressed, use -v[v]... for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), snapshot length 262144 bytes
01:26:56.188414 IP 172.16.1.60.1332 > 172.16.1.50.69: TFTP, length 59, RRQ "boot/bootx64.efi" octet tsize 0 blksize 1482 windowsize 4
01:26:56.189458 IP 172.16.1.60.1333 > 172.16.1.50.69: TFTP, length 51, RRQ "boot/bootx64.efi" octet blksize 1482 windowsize 4
01:26:56.225401 IP 172.16.1.60.1334 > 172.16.1.50.69: TFTP, length 50, RRQ "boot/grubx64.efi" octet blksize 512 windowsize 4

grub> echo $prefix

(tftp,172.16.1.50)/boot/grub

Screenshot of Grub> Info

For what it's worth, I have validated that the Apache2 directories are being served correctly and in fact, with the above config I am able to PXE boot BIOS based systems using the pxelinux.0.

For whatever reason UEFI systems (or in my case Hyper-V Gen2) get 'stuck' at the grub> menu.

Any help or advice would be appreciated. I know I'm close.

Cheers!

boot

0 Answers