virt-spawn

#!/bin/bash

usage() {
cat <<USAGE
usage: $0 options -- VARIABLE1=value1 ...

Wrapper around virt-builder and virt-install with dnsmasq support.

This script helps with spawning VMs by calling virt-builder and virt-install
tools with proper parameters and also modifying dnsmasq configuration to setup
hostnames properly sending SIGHUP to dnsmasq to refresh.

All VMs created by this tool has root password set to "redhat" but your public
key is also automatically deployed into the VM.

The script is best to use with BATS testing suite for running installation and
integration tests. It was developed for The Foreman open-source project.

Before you start, install required dependencies:

  $0 --install-deps

OPTIONS:
  --help | -h
        Show this message

  --name | -n
        Image name, default: $NAME

  --distro | -d
        Distribution base image for virt-builder. default: $DISTRO

  --os-variant | -t
        OS variant for virt-install. To get the full list use
        virt-install --os-variant=list command. Default: $DISTRO

  --ram | -r
        Amount of memory for the VM in kbytes, default: $RAM

  --disk | -k
        Size of the image, default $SIZE

  --force | -f
        Overwrite target image and VM if they exist

  --no-sudo
        Do not use sudo for building and running VM - you will need to
        set --image-dir accordingly too when running under regular user.

  --build-opts [options]
        Addtional options for virt-builder (e.g. "--size 50G").
        You can only provide this option once, enquote if you need more
        options.

  --image-dir [path]
        Target images path
        Default: $IMAGEDIR

  --domain [domain]
        Domain suffix like "mycompany.com", default: $DOMAIN

  --subnet [subnet]
        Subnet to be used for writing DHCP/DNS configuration
        Default: $SUBNET (note there is no suffix or period)

  --pub-key [key]
        Install this public ssh key
        Default: $PUBKEY

  --script [name]
        BATS script to execute during first boot (can be any shell command)
        Can specify multiple times for multiple commands (scripts)
        Default: $SCRIPT

  --install-deps
        Install required dependencies

Integration with dnsmasq is optional, but if you want to take advantage of it,
configure your local dnsmasq to be your caching DNS server with exception for
locally provisioned VMs:

  # cat /etc/dnsmasq.d/virt-spawn
  addn-hosts=/var/lib/libvirt/dnsmasq/default.addnhosts

  # cat /etc/dnsmasq.d/caching
  bind-interfaces
  cache-size=500
  listen-address=127.0.0.1
  resolv-file=/etc/resolv.dnsmasq

  # cp /etc/resolv.conf /etc/resolv.dnsmasq
  # chattr +i /etc/resolv.conf

  systemctl enable dnsmasq
  systemctl start dnsmasq

Example:

  virt-spawn -n my-nightly-foreman -f
  virt-spawn -n rc-foreman -- "FOREMAN_REPO=rc" "MYVAR=value"
  virt-spawn -n stable-foreman -- "FOREMAN_REPO=releases/1.5"
  virt-spawn -n bz981123 -- "KOJI_BUILD=http://mykoji.blah/taskinfo?taskID=97281"
  virt-spawn -n my-own-script --script fb-xyz.bats -- BATS_REPOOWNER=lzap BATS_BRANCH=test

USAGE
}

ACTION=build
NAME=nightly
DOMAIN=local.lan
DISTRO=centos-6
OSVARIANT=rhel6
IMAGEDIR=/var/lib/libvirt/images
SUBNET='192.168.122'
PUBKEY=$HOME/.ssh/id_rsa.pub
FORCE=0
RAM=3200
SIZE=6G
BUILD_OPTS=""
SUDO=sudo
SCRIPTS=()

if ! options=$(getopt -o hfn:d:r:k:t: -l help,name:,distro:,ram:,disk:,build-opts:,pub-key:,install-deps,image-dir:,domain:,script:,no-sudo,subnet:,os-variant:,force -- "$@"); then
  exit 1
fi

eval set -- $options

while [ $# -gt 0 ]; do
    case $1 in
    --name|-n) NAME="$2" ; shift ;;
    --distro|-d) DISTRO="$2" ; shift ;;
    --os-variant|-t) OSVARIANT="$2" ; shift ;;
    --image-dir|-p) IMAGEDIR="$2" ; shift ;;
    --domain) DOMAIN="$2" ; shift ;;
    --ram|-r) RAM="$2" ; shift ;;
    --disk|-k) SIZE="$2" ; shift ;;
    --subnet) SUBNET="$2" ; shift ;;
    --build-opts) BUILD_OPTS="$2" ; shift ;;
    --pub-key) PUBKEY="$2" ; shift ;;
    --script) SCRIPTS+=("$2") ; shift ;;
    --install-deps) ACTION=installdeps ; shift ;;
    --no-sudo) SUDO='' ;;
    --force|-f) FORCE=1 ;;
    --help|-h) usage;  exit ;;
    (--) shift; break;;
    (-*) echo "$0: error - unrecognized option $1" 1>&2; exit 1;;
    (*) break;;
    esac
    shift
done

if [ $ACTION = installdeps ]; then
  echo "Installing virtualization dependencies"
  $SUDO yum -y install openssl virt-install libguestfs libguestfs-tools util-linux sudo libxml2 fortune-mod
  exit 0
fi

echo "Parsing extra arguments"
EXPORTS=()
BATS_REPOOWNER="theforeman"
BATS_BRANCH="master"
while [ $# -gt 0 ]; do
  echo "$1"; eval "$1"
  EXPORTS+=("export $1")
  shift
done

FQDN=${NAME}.${DOMAIN}
IMAGE=${IMAGEDIR}/$FQDN.img
MAC="52:54:01$(echo "$(hostname)${FQDN}" | openssl dgst -md5 -binary | hexdump -e '/1 ":%02x"' -n 3)"
TMP_BOOTSCRIPT=$(mktemp virt-builder-boot-script-XXXXXXXXXX)
TMP_SCRIPT=$(mktemp virt-builder-build-script-XXXXXXXXXX)
trap "rm -f $TMP_BOOTSCRIPT $TMP_SCRIPT" EXIT

if [[ FORCE -eq 0 ]]; then
  if [[ -f ${IMAGE} ]]; then
    echo "Image $IMAGE exists, use --force Luke!"; exit 1
  fi
  if $SUDO virsh domstate $FQDN >/dev/null 2>&1; then
    echo "Domain $FQDN exists, use --force Luke!"; exit 1
  fi
fi

echo "Stopping and removing $FQDN if exists"
$SUDO virsh destroy $FQDN >/dev/null 2>&1
$SUDO virsh undefine $FQDN >/dev/null 2>&1

echo "Reading your public ssh key"
PUBLIC_KEY=$(cat $PUBKEY)

echo "Removing existing DHCP/DNS configuration from libvirt"
netdump="$SUDO virsh net-dumpxml default"
virsh_dhcp=$($netdump | xmllint --xpath "/network/ip/dhcp/host[@mac='$MAC']" - 2>/dev/null)
virsh_dns=$($netdump | xmllint --xpath "/network/dns/host/hostname[text()='$FQDN']/parent::host" - 2>/dev/null)
$SUDO virsh net-update default delete ip-dhcp-host --xml "$virsh_dhcp" --live --config 2>/dev/null
$SUDO virsh net-update default delete dns-host --xml "$virsh_dns" --live --config 2>/dev/null

while true; do
  AIP="${SUBNET}.$(( ( RANDOM % 250 )  + 2 ))"
  echo "Checking if random IP $AIP is not in use"
  $netdump | xmllint --xpath "/network/ip/dhcp/host[@ip='$AIP']" - &>/dev/null || break
done

echo "Deploying DHCP/DNS configuration via libvirt for $AIP"
$SUDO virsh net-update default add-last ip-dhcp-host --xml "<host mac='$MAC' name='$FQDN' ip='$AIP'/>" --live --config
$SUDO virsh net-update default add-last dns-host --xml "<host ip='$AIP'><hostname>$FQDN</hostname></host>"  --live --config

cat <<EOFBS > $TMP_BOOTSCRIPT
#!/bin/bash
$(for ix in ${!EXPORTS[*]}; do printf "%s\n" "${EXPORTS[$ix]}"; done)
export HOME=/root
cd \$HOME
type restorecon && restorecon -RvvF .ssh
while ! ping -c1 -w10 8.8.8.8 &>/dev/null; do true; done
set -x
type git || yum -y install git || (apt-get update && apt-get -y install git)
git clone https://github.com/sstephenson/bats.git && bats/install.sh /usr/local
git clone https://github.com/$BATS_REPOOWNER/foreman-bats.git -b $BATS_BRANCH && foreman-bats/install.sh /usr/local
git clone https://github.com/lzap/bin-public.git
export PATH=/usr/local/bin:/root/bin-public:\$PATH
[[ -n "\$KOJI_BUILD" ]] && fb-setup-koji.bats
$(export IFS=$'\n'; echo "${SCRIPTS[*]}")
EOFBS

cat <<EOFS > $TMP_SCRIPT
#!/bin/bash
# debian/ubuntu image reconfiguration
type dpkg && dpkg-reconfigure openssh-server

# ssh key deployment
mkdir /root/.ssh
echo $PUBLIC_KEY > /root/.ssh/authorized_keys
chmod 700 /root/.ssh
chmod 600 /root/.ssh/authorized_keys
true
EOFS

echo "Building new image based on $DISTRO"
$SUDO virt-builder $DISTRO \
  -o $IMAGE \
  --root-password password:redhat \
  --hostname $FQDN \
  --run $TMP_SCRIPT \
  --firstboot $TMP_BOOTSCRIPT \
  --size $SIZE \
  $BUILD_OPTS \
  || exit 2

echo "Spawning new VM with MAC address $MAC"
$SUDO virt-install --import \
  --cpu host \
  --vcpus $(nproc) \
  --os-variant $OSVARIANT \
  --name $FQDN \
  --ram $RAM \
  --disk path=$IMAGE,format=raw,bus=virtio \
  --graphics spice \
  --noautoconsole \
  --network=default,mac=$MAC,model=virtio \
  --force \
  || exit 3
echo "First boot initiated and the VM is resizing drive"

echo "Refreshing local dnsmasq configuration"
$SUDO pkill -SIGHUP dnsmasq

# set hostname on the libvirt dns
echo "Waiting for IP address to show up"
i=0; until [ $i -ge 200 ] || IPADDR=$(arp -an | grep $MAC | grep -Eo '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}'); do
  i=$((i + 1)); sleep 1
done
echo "The new guest received $IPADDR (expected $AIP)"

echo "Done! Your guest networking should be up and running soon."
echo "Login and watch virt-sysprep-firstboot.log for progress."
echo
echo " ssh root@$FQDN"
echo " http://$FQDN"
echo " https://$FQDN"
echo
type fortune &>/dev/null && fortune