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Running the Provisioning OS via PXE

  1. First, you need to get five files. These are distributed together as pxe-artifacts.zip:

    • bootx64.efi This is the shim binary that is hard-coded to launch grubx64.efi.
    • grubx64.efi This is a copy of the "noprefix" version of GRUB2.
    • grub.cfg Configuration file for GRUB that directs it to load the following files.
    • vmlinuz The Linux kernel binary.
    • initrd.img An initrd containing Trident and a placeholder Trident configuration.

  2. Move the first four files to a tftp directory to serve them:

    mkdir tftp
    cp bootx64.efi grubx64.efi grub.cfg vmlinuz tftp/

  3. Insert your own Host Configuration into the initrd. Trident reads its configuration from /etc/trident/config.yaml inside the initramfs. To replace the placeholder configuration with your own, unpack the initrd, copy your file in, and repack it:

    mkdir initrd-work && cd initrd-work
    zstdcat ../initrd.img | cpio -idm --no-absolute-filenames
    cp ../trident.yaml etc/trident/config.yaml
    find . | cpio -o -H newc | zstd > ../tftp/initrd.img
    cd .. && rm -rf initrd-work

    Note: Trident initrds are zstd-compressed. If your image uses gzip instead, replace zstdcat with zcat and zstd with gzip.

    For details on the Host Configuration format, see the Host Configuration reference.

  4. Create disk.img to use as an emulated hard drive:

    truncate -s 20G disk.img

  5. Run TPM emulator (the swtpm call needs to be rerun each time you launch QEMU).

    mkdir /tmp/mytpm1
    swtpm socket \
        --tpmstate dir=/tmp/mytpm1 \
        --ctrl type=unixio,path=/tmp/mytpm1/swtpm-sock \
        --log level=20

  6. While swtpm is still running, launch QEMU in a second terminal.

    qemu-system-x86_64 -machine q35 -cpu host -smp 2 -m 4G -accel kvm -serial stdio \
        -netdev user,id=net0,tftp=./tftp,bootfile=/bootx64.efi \
        -device virtio-net-pci,netdev=net0 \
        -drive if=pflash,format=raw,file=/usr/share/OVMF/OVMF_CODE_4M.fd,readonly=on \
        -chardev socket,id=chrtpm,path=/tmp/mytpm1/swtpm-sock \
        -tpmdev emulator,id=tpm0,chardev=chrtpm \
        -device tpm-tis,tpmdev=tpm0 \
        -drive format=raw,file=disk.raw