Pre-install

  • grab 4gb usb key, 8gb usb key, and download Vanilla .iso from Alpine. Burn ISO to 8gb stick

  • Boot to system, make sure you have drivers, and install to 4GB stick. Recommended step: remove other storage in prior stage.

  • Install

After installation

  • Use second PC and Gparted to remove swap, fix [inst-root]/etc/fstab (comment out the swap partition), and resize the [inst-root] so it’s as small as you can go (512MB IIRC?)

  • Back your disk up (sdd is 4GB usb on my 2nd machine): dd if=/dev/sdd of=/backup/location/sdd.img && dd if=/dev/sdd3 of=/backup/location/sdd3.img

  • Boot your system again. Time for cleanup:

  • Remove unnecesary firmware and add minimal tools with apk add linux-firmware-none wget tftp-hpa

  • remove drivers you don’t need in /lib/modules/[kernel-version]/kernel/drivers/, run depmod to fix dependency issues

  • Plug your stick back to your 2nd PC, fire up Gparted again, create small partition (160MB or so), mount sdd3 to /source, sdd2 to /dest/ and copy root files accross with cp -afv /source/* /dest/. Fix [inst-root]/etc/fstab and boot entry in boot partition (sda1) so it boots from /dev/sda2 instead of sda3 (or its UUID…).

  • create image of “sda2”

Edit initramFS

  • Unpack it with zcat /boot/initrd-$(uname -r).img | cpio -idmv (You can rename it to .gz and use gnome archiver to extract it, xarchiver knows how to extract CPIO archive as well)

  • Copy tftp, wget from [inst-root]/usr/bin to initramfs/usr/bin/

  • Add necesary drivers (and their dependencies) from [inst-root]/lib/modules/[kernel-version]/kernel/drivers/net/ethernet and make sure to add them (and their dependencies) in [initramfs]/lib/modules/[kernel-version]/modules.dep!

  • Edit [initramfs]/init. I’ve added modprobe for drivers, custom kernel options, (tftps and tftpf (for PXE menu parameters)), then use those options to tftp-download a tiny SH from a server. The script uses wget to download rootFS IMG and mount it as /sysroot in RAM. Why Wget? Because it’s way faster than TFTP (100Mbps vs 6Mbps in VM test), and because it’s TCP.

  • mkdir [initramfs]/etc/network

  • mkdir [initramfs]/etc/network/{if-up.d,if-pre-up.d,if-pre-down.d,if-down.d}

  • echo to [initramfs]/etc/network/interfaces:

auto lo eth0
iface lo inet loopback
iface eth0 inet dhcp

  • mkdir [initramfs]/var/run

  • mkdir [initramfs]/usr/share/udhcpc

  • cp [inst-root]/usr/share/udhcpc/default.script [initramfs]/usr/share/udhcpc

  • Package initramFS from inside of the folder with find . | cpio -ov --format=newc | gzip -9 >../initramfs-vanilla

Final steps

  • Deploy the custom initramfs to PXE server

  • Deploy the DD’d dd the img to PXE server

  • Try to boot and debug. Trial and error in do-while-true loop.