spawn.sh

#!/bin/bash

#set -x
VIRSH=$(which virsh)
VIRTCLONE=$(which virt-clone)
GUESTFISH=$(which guestfish)
VIRTCOPY=$(which virt-copy-in)
DISTRO=$1
VM=$2
CWD="/var/lib/libvirt/images"

### Am i Root check
if [ "$(id -u)" != "0" ]; then
  echo "This script must be run as root, or preceded by sudo."
  echo "If sudo does not work, contact your system administrator."
  exit 1
fi

## Check for virsh command
which virsh
if [ $? -ne "0" ]; then
  echo "virt-clients not installed, check requirements into README"
  exit 1
fi

usage () {
  echo "usage: $0 [distro] [instance name]"
  echo "possible distros: debian10 / debian 11 / ubuntu18 / ubuntu20"
  exit 1
}

### check the distro ( first ) argument
case "$1" in
### help
  -h | help | --help)
    usage
  ;;

### debian11
  -d11 | debian11 | d11)
    echo "Debian 11 (bullseye) selected"
  ;;

### ubuntu18
  -u18 | ubuntu18 | u18)
    echo "Ubuntu 18.04 (bionic) selected"
  ;;

### ubuntu20
  -u20 | ubuntu20 | u20)
    echo "Ubuntu 20.04 (focal) selected"
  ;;

### otherwise, we show usage
  *)
    usage
    exit 0
  ;;
esac

if [ -z "$2" ]; then
  echo "you must provide an instance name"
  usage
  exit 1
elif [ "x$2" = x ]; then
  echo "empty string on instance name"
  exit 1
fi

check_exitcode () {
  if [ $? -ne "0" ]; then
    echo "WARN $? exitcode"
  fi
}

### check the instance ( second ) argument
### we want to make sure that the inputs are valid when it comes to distro and name
### the instance name must be provided and alphanumeric
check_aln () {
  echo $VM | egrep -q "\W"
}

check_aln
if [ $? -eq "0" ]; then
  echo "We only admit alphanumerical named guests in this establishment, sorry."
  exit 1
fi

check_existing () {
  $VIRSH list --name | grep -w $DISTRO.$VM > /dev/null 2>&1
}

## check if we are trying to create a machine that already exists and is running (!)
## for example , as a consequence of a typo
check_existing
if [ $? -eq "0" ]; then
  echo "an instance called $DISTRO.$VM already exists and is running. Bailing out."
  exit 1
fi

## check if we are not risiking to overwrite some important image

if [ $VM == "original" ]; then
  echo "Sorry, "original" is a bad name here."
  exit 1
fi

if [ $VM == "golden" ]; then
  echo "Sorry, "golden" is a bad name here."
  exit 1
fi

## check if we have the golden image

if [ ! -f $CWD/${DISTRO}.golden.img ]; then
  echo "Sorry, we don't have a golden image ready for ${DISTRO}."
  echo "Use ./build-installation.sh ${DISTRO} first, then"
  echo "run ./prepare-golden.sh ${DISTRO}. Then retry with this command."
  exit 1
fi

## create a clone, referencing only to the copy
qemu-img create -b $CWD/${DISTRO}.golden.img -F qcow2 -f qcow2 $CWD/${DISTRO}.${VM}.qcow2
check_exitcode

### clone the configuration file for kvm
$VIRSH dumpxml $DISTRO.original > /tmp/$DISTRO.original.xml
check_exitcode

### change the cache type from none to unsafe
sed -i 's/none/unsafe/g' /tmp/$DISTRO.original.xml

# clone the configuration file using the original distro one, changing the image reference to point at the prepared image
$VIRTCLONE --original-xml /tmp/$DISTRO.original.xml --name ${DISTRO}.${VM} --preserve-data --file $CWD/${DISTRO}.${VM}.qcow2
check_exitcode


### inject standard SSH host keys ( the same for all possible machines we clone ).
## first step is to make sure the permissions for our local files are correct
# chmod 600 keys/ssh_host*
# chmod 644 keys/*.pub
#
# ## copy them into the clone
# /usr/bin/virt-copy-in -d ${DISTRO}.${VM} keys/ssh_host* /etc/ssh/

# /usr/bin/virt-copy-in -d ${DISTRO}.${VM} files/rc.local /etc/rc.local
# /usr/bin/virt-copy-in -d ${DISTRO}.${VM} $PWD/files/jenkins_authorized_keys /root

# As a backup plan, we make sure that the guest will generate some host keys if none are present
# ( after all, we removed the host keys in the golden image preparation script).

if [ -f /root/custom_authorized_keys ]; then
  cp /root/custom_authorized_keys /tmp/authorized_keys
  $VIRTCOPY -d ${DISTRO}.${VM} /tmp/authorized_keys /root/
  rm /tmp/authorized_keys
fi

$GUESTFISH -d ${DISTRO}.${VM} -i upload - /etc/rc.local <<EOF
#!/bin/bash

  if [ ! -d /root/.ssh ]; then
    mkdir /root/.ssh
  fi

  if [ -f /root/custom_authorized_keys ]; then
    cp /root/custom_authorized_keys /root/.ssh/authorized_keys
    chmod 700 /root/.ssh
    chmod 600 /root/.ssh/authorized_keys
  fi

  if [ ! -f /etc/ssh/ssh_host_dsa_key ]; then
     ssh-keygen -A
  fi

## preserving this temporarily in case i broke older distros or RHEL
#
#  if [ ! -f /etc/ssh/ssh_host_dsa_key ]; then
#     ssh-keygen -f /etc/ssh/ssh_host_rsa_key -N '' -t rsa > /dev/null 2>&1
#     ssh-keygen -f /etc/ssh/ssh_host_dsa_key -N '' -t dsa > /dev/null 2>&1
#  fi

  ## This reload the selinux policy for rpm based distros
  if [ -f /sbin/restorecon ]; then
    /sbin/restorecon -R -v /root/.ssh
  fi
exit 0
EOF

#systemd...
if [ $DISTRO = "centos7" ] || [ $DISTRO = "debian9" ] || [ $DISTRO = "debian10" ] || [ $DISTRO = "debian11" ];  then
    $GUESTFISH -d ${DISTRO}.${VM} -i command "chmod a+x /etc/rc.local"
fi

if [ $DISTRO = "ubuntu18" ] || [ $DISTRO = "ubuntu20" ]; then
    $GUESTFISH -d ${DISTRO}.${VM} -i command "chmod a+x /etc/rc.local"
    $GUESTFISH -d ${DISTRO}.${VM} -i command "systemctl enable rc-local.service"
    $GUESTFISH -d ${DISTRO}.${VM} -i command "systemctl start rc-local.service"
fi

if [ $DISTRO = "debian6" ]; then
$GUESTFISH -d ${DISTRO}.${VM} -i upload - /etc/apt/sources.list <<EOF
    deb http://archive.debian.org/debian/ squeeze main non-free contrib
    deb-src http://archive.debian.org/debian/ squeeze main non-free contrib
    deb http://archive.debian.org/debian-security/ squeeze/updates main non-free contrib
    deb-src http://archive.debian.org/debian-security/ squeeze/updates main non-free contrib
EOF
fi

# start the machine!
$VIRSH start ${DISTRO}.${VM}
check_exitcode

extract_address () {
  # extract the mac address from the configuration file
  MAC=`grep -ir "mac address" /etc/libvirt/qemu/${DISTRO}.${VM}.xml | awk -F"'" '{print $2}'`
  ### grep for the mac address in the dhcp leases if any, else use arp to find it
  if [ -f /var/lib/libvirt/dnsmasq/default.leases ]; then
    IP=`cat /var/lib/libvirt/dnsmasq/default.leases | grep -i $MAC | awk '{print $3}'`
  else
    arp -a -i virbr0 | grep -i $MAC > /tmp/arp.txt
    IP=`grep -oP '\(\K[^)]+' /tmp/arp.txt`
  fi
}

extract_address
if [ -z $IP ]; then
  echo "Waiting for the instance to boot"
  sleep 40
else
  echo "$IP has been assigned to ${DISTRO}.${VM} by DHCP"
fi

extract_address
echo "$IP has been assigned to ${DISTRO}.${VM} by DHCP"