get networking facts from bridged libvirt guests

myvirt-facts

#!/bin/bash

# myvirt-facts - get networking facts from bridged libvirt guests
# https://gist.github.com/koniu/837a574e7af377e37d67
# author <[email protected]>
#
# usage:
#   myvirt-facts <domain> [ip|arp|hostname]
#
# for convenience symlink to: 
#   myvirt-ip
#   myvirt-arp
#   myvirt-hostname
#   myvirt-ssh


domains() {
  echo
  echo Domains:
  virsh -q list --all
  echo
}

fail() {
  domains
  exit 1
}

usage() {
  echo "usage: $0 <domain>"
  fail
}

get_host_ip() {
  ip addr | grep 'state UP' -A2 | tail -n1 | awk '{print $2}' | cut -f1  -d'/'
}

fill_arp() {
  for i in $(seq 1 254); do
    ping -c 1 -n -q -r  -t 1 -s 1  -W 1 \ 
      `get_host_ip | cut -d. -f1-3`.$i > /dev/null &
  done
}

get_guest_state() {
  virsh -q domstate $1
}

get_guest_iface() {
  virsh -q domiflist $1 || fail
}

get_guest_arp() {
  get_guest_iface $1 | awk '{print $5}'
}

get_guest_ip() {
  arp -en | grep `get_guest_arp $1` | head -n1 | awk '{print $1}'
}

get_guest_hostname() {
  host `get_guest_ip $1` | cut -d\   -f5 | cut -d\.  -f1 
}


# no domain name provided
[ -z $1 ] && usage

# refresh arp table
fill_arp

# output based on invocation
case `basename $0` in
  *virt-facts)
    state=`get_guest_state $1`
    iface=`get_guest_iface $1`
    arp=`get_guest_arp $1`
    ip=`get_guest_ip $1`
    hostname=`get_guest_hostname $1`
    case $2 in
      "") 
        echo "Domain:    $1"
        echo "State:     $state"
        echo
        echo "Hostname:  $hostname"
        echo "IP:        $ip"
        echo "ARP:       $arp"
      ;;  
      *)  
        get_guest_$2 $1
    esac
  ;;  
  *virt-ssh)
    ip=`get_guest_ip $1`
    cmd=$(echo $0 | cut -d\- -f2)
    shift 1
    echo % $cmd -l $USER $ip $@
    $cmd -l $USER $ip 
    break
  ;;  
  *virt-*) get_guest_$(echo $0 | cut -d\- -f2) $1 ;;
  *) echo wrong name; fail ;;
esac