Metal Stack Hammer

Hammer is used to boot a bare metal server via PXE together with the Metal Stack kernel. Hammer is a initrd which runs a small golang binary as init process. This does the following actions:

• Ensures all interfaces are up
• Check if the server was booted in UEFI, if not modify the bios to uefi and reboots
• Wipes as existing disks by either:
  • run secure erase if possible by using the mechanism in modern disks, this is true for most SSD´s and NVME disks.
  • If not possible run mkfs.ext4 --discard on the disks.
• Gather HW information and report them back to metal-api:
  • CPU Core count
  • Memory count
  • Disks with their size and device path
  • Network adapters which have an active uplink with their interface name, own mac address and mac address of the switch chassis where this network card is connected to. 2 distinct switch chassis are required.
  • IPMI interface with mac and ipaddress.
  • create a metal user on IPMI with a strong password
• Set BIOS boot order to contain only PXE and Hard Disk as possible options.
• Wait until a machine create command was issued from metal-api

Local Testing

make clean initrd vagrant-up

Create a PXE boot initrd with u-root

In order to be able to create an initrd image which is suitable to boot a bare metal server with the required tools to discover and install the target os, we use u-root.

Quickstart

• download u-root:

go get -u github.com/u-root/u-root

• build the initrd

make initrd

check content

cpio -itv < metal-hammer-initrd.img

start it

make vagrant-up