container-demo.sh

#!/bin/bash

. /etc/os-release

IMAGE="container-demo.img"

die() { echo "FATAL: $@" >&2 ; exit 1 ; }
info() { echo "INFO: $@" ; }

install_dependencies() {
  info "Checking dependencies"
  if [[ "$ID" == "fedora" ]]; then
    for PKG in qemu-system-x86 libguestfs-tools-c; do
      if ! dnf list installed $PKG 2>&-; then
        die "Please install '$PKG'"
      fi
    done
  elif [[ "$ID" == "ubuntu" ]]; then
    info "Please ensure to setup libguestfs correctly: http://libguestfs.org/guestfs-faq.1.html#downloading-installing-compiling-libguestfs"
    info "Eventually you need to run this script using sudo"
    for PKG in qemu-system-x86 libguestfs-tools; do
      if ! dpkg -s $PKG >/dev/null ; then
        die "Please install '$PKG'"
      fi
    done
  else
    die "Unsupported operating system '$ID'. Get a real OS."
  fi
}

install_dependencies

if ! virt-builder -v -x centos-7.3 \
                --no-network \
                --smp 4 --memsize 2048 \
                --output $IMAGE \
                --format qcow2 \
                --size 20G \
                --hostname container-demo \
                --root-password password: \
                --run-command "echo -e Login as \'root\' to proceed.\\\\n >> /etc/issue" \
                --firstboot-command \
                "sudo yum install -y yum-utils device-mapper-persistent-data lvm2 ; 
                sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo ; 
                sudo yum -y install docker-ce ;
                systemctl enable docker ;
                systemctl start docker"
then
    die "Failed on virt-builder. Unable to create image."
fi

QEMU_CMD=/usr/libexec/qemu-kvm
if [[ ! -x $QEMU_CMD ]]
then
    QEMU_CMD=qemu-system-x86_64
fi

$QEMU_CMD \
        --cpu host --machine accel=kvm:tcg \
        --nographic -m 2048 -smp 4 \
        -net nic \
        -object rng-random,id=objrng0,filename=/dev/urandom -device virtio-rng-pci,rng=objrng0 \
        -net user \
        $IMAGE