We bought a bunch of very cheap low end HPE DL120 server. Enough to warrant a completely automated installation setup. Shouldn't be that much of a deal, right? Get dnsmasq up and running, feed it a preseed.cfg and be done with it. In practise it took us more hours then we expected.

Setting up the hardware

Our hosts are equipped with an additional 10G dual port NIC and we'd like to use this NIC for PXE booting. That's possible, but it requires you to switch to UEFI boot. Actually it enables you to boot from any available NIC.

Setting up dnsmasq

We decided to just use the packaged debian-installer from jessie and do some ugly things like overwritting files in /usr/lib via ansible later on. So first of all install debian-installer-8-netboot-amd64 and dnsmasq, then enroll our additional config for dnsmasq, ours looks like this:

pxe-service=X86-64_EFI, "Boot UEFI PXE-64", bootnetx64.efi

Now you've to link /usr/lib/debian-installer/images/8/amd64/text/bootnetx64.efi to /usr/lib/debian-installer/images/8/amd64/text/debian-installer/amd64/bootnetx64.efi. That got us of the ground and we had a working UEFI PXE boot that got us into debian-installer.

Feeding d-i the preseed file

Next we added some grub.cfg settings and parameterized some basic stuff to be handed over to d-i via the kernel command line. You'll find the correct grub.cfg in /usr/lib/debian-installer/images/8/amd64/text/debian-installer/amd64/grub/grub.cfg. We added the following two lines to automate the start of the installer:

set default="0"
set timeout=5

and our kernel command line looks like this:

 linux    /debian-installer/amd64/linux vga=788 --- auto=true interface=eth1 netcfg/dhcp_timeout=60 netcfg/choose_interface=eth1 priority=critical preseed/url=tftp:// quiet

Important points:

  • tftp host IP is our dnsmasq host.
  • Within d-i we see our NIC we booted from as eth1. eth0 is the shared on-board ilo interface. That differs e.g. within grml where it's eth2.

preseeed.cfg, GPT and ESP

One of the most painful points was the fight to find out the correct preseed values to install with GPT to create a ESP (EFI system partition) and use LVM for /.

Relevant settings are:

# auto method must be lvm
d-i partman-auto/method string lvm
d-i partman-lvm/device_remove_lvm boolean true
d-i partman-md/device_remove_md boolean true
d-i partman-lvm/confirm boolean true
d-i partman-lvm/confirm_nooverwrite boolean true
d-i partman-basicfilesystems/no_swap boolean false

# Keep that one set to true so we end up with a UEFI enabled
# system. If set to false, /var/lib/partman/uefi_ignore will be touched
d-i partman-efi/non_efi_system boolean true

# enforce usage of GPT - a must have to use EFI!
d-i partman-basicfilesystems/choose_label string gpt
d-i partman-basicfilesystems/default_label string gpt
d-i partman-partitioning/choose_label string gpt
d-i partman-partitioning/default_label string gpt
d-i partman/choose_label string gpt
d-i partman/default_label string gpt

d-i partman-auto/choose_recipe select boot-root-all
d-i partman-auto/expert_recipe string \
boot-root-all :: \
538 538 1075 free \
$iflabel{ gpt } \
$reusemethod{ } \
method{ efi } \
format{ } \
. \
128 512 256 ext2 \
$defaultignore{ } \
method{ format } format{ } \
use_filesystem{ } filesystem{ ext2 } \
mountpoint{ /boot } \
. \
1024 4096 15360 ext4 \
$lvmok{ } \
method{ format } format{ } \
use_filesystem{ } filesystem{ ext4 } \
mountpoint{ / } \
. \
1024 4096 15360 ext4 \
$lvmok{ } \
method{ format } format{ } \
use_filesystem{ } filesystem{ ext4 } \
mountpoint{ /var } \
. \
1024 1024 -1 ext4 \
$lvmok{ } \
method{ format } format{ } \
use_filesystem{ } filesystem{ ext4 } \
mountpoint{ /var/lib } \
# This makes partman automatically partition without confirmation, provided
# that you told it what to do using one of the methods above.
d-i partman-partitioning/confirm_write_new_label boolean true
d-i partman/choose_partition select finish
d-i partman-md/confirm boolean true
d-i partman/confirm boolean true
d-i partman/confirm_nooverwrite boolean true

# This is fairly safe to set, it makes grub install automatically to the MBR
# if no other operating system is detected on the machine.
d-i grub-installer/only_debian boolean true
d-i grub-installer/with_other_os boolean true
d-i grub-installer/bootdev  string /dev/sda

I hope that helps to ease the processes to setup automated UEFI PXE installations for some other people out there still dealing with bare metal systems. Some settings took us some time to figure out, for example d-i partman-efi/non_efi_system boolean true required some searching on codesearch.d.n (amazing ressource if you're writing preseed files and need to find the correct templates) and reading scripts on git.d.o where you'll find the source for partman-* and grub-installer.


Thanks especially to P.P. and M.K. to figure out all those details.