Use docker to generate a baremetal-friendly iso image

baremetal Dockerfile

# docker build -t linux-live .
# docker run -ti -v `pwd`/out:/tmp linux-live ./build-perf.sh
# kvm -cdrom out/linux-x86_64.iso
FROM ubuntu:18.04
RUN echo deb http://us.archive.ubuntu.com/ubuntu bionic-backports main restricted universe multiverse >> /etc/apt/sources.list
RUN apt update
ARG DEBIAN_FRONTEND=noninteractive
ENV KERNEL 5.4.0-37-generic
RUN apt-get install --no-install-recommends -y linux-image-$KERNEL git squashfs-tools mkisofs zip xz-utils  systemd-sysv ca-certificates vim-nox cpio sudo iproute2 networkd-dispatcher network-manager networkd-dispatcher  netplan pciutils
WORKDIR /root
RUN git clone https://github.com/Tomas-M/linux-live
WORKDIR /root/linux-live
RUN sed -i "s:^KERNEL.*:KERNEL=$KERNEL:" config
RUN sed -i 's/TIMEOUT 140/TIMEOUT 1/' bootfiles/syslinux.cfg
RUN sed -i 's/ALL$/NOPASSWD:ALL/' /etc/sudoers
RUN echo "[Network]\nDHCP=yes" >> /etc/systemd/network/00-dhcp.network
RUN echo "\n[keyfile]\nunmanaged-devices=*,except:type:ethernet\n" >> /etc/NetworkManager/NetworkManager.conf