startup.sh-minimalist

#!/bin/bash

set -eou pipefail

# Check to see if the CPU supports Virtualisation extensions
vtxcores=$(egrep -c '(vmx|svm)' /proc/cpuinfo)
if [ $vtxcores -gt 0 ]; then
  # Good news !!
  echo "Host reports "$vtxcores" VT-x cores available. This will probably work..."
else
  # Bad News !!
  echo "Host CPU Reports 0 VT-x cores available, unable to proceed."
  echo "Please enable VT-x or Virtualisation extensios in the underlying host platform and try again."
  exit 0
fi

# Do some necessary setup in the environment so Vagrant will work.
chown root:kvm /dev/kvm
/usr/sbin/libvirtd --daemon
/usr/sbin/virtlogd --daemon
# drop the user into the /vagrant folder, where the context of their box will be extablishsed.
cd /vagrant


# In case this container has been run previously, and there is a Vagrantfile in the /vagrant folder, then we should 
#  support th euser by passing environment variables into it to set the CPU/RAM/DISK requested by the user by way of
#  the ENVironment variables passed from docker.
if test -f Vagrantfile.orig; then
  mv Vagrantfile.orig Vagrantfile
fi
if test -f Vagrantfile; then
  awk -v line=$(awk '/end/{x=NR}END{print x}' Vagrantfile) 'NR==FNR{a[NR]=$0;next}{if(FNR==line){for(i=1;i<=NR;i++)print a[i]}print}' text_to_insert.txt Vagrantfile | awk 'NF' > Vagrantfile.out
  mv Vagrantfile.out Vagrantfile
  envsubst '$CPU,$MEMORY,$DISK_SIZE' < Vagrantfile > Vagrantfile.tmp
  mv Vagrantfile Vagrantfile.orig
  mv Vagrantfile.tmp Vagrantfile
#  vagrant destroy -f
  vagrant up
fi

exec "$@"