WIP Add KVM host backup recipe

Add a recipe that configures scripts for live backups of VM images via
libvirt and borg.

site-cookbooks/kosmos_kvm/files/backup_vm.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+# GENERATED BY CHEF
+# DO NOT EDIT
+set -e
+
+REPOSITORY=$BORG_REPO
+
+echo "Starting backup of VM: $1"
+
+echo "Dumping domain XML to /root/backups/vm_meta/$1.xml"
+virsh dumpxml --migratable $1 > /root/backups/vm_meta/$1.xml
+
+virsh snapshot-create-as --domain $1  \
+        --name hotswap.qcow2  \
+        --no-metadata         \
+        --atomic              \
+        --quiesce             \
+        --disk-only           \
+        --diskspec vda,snapshot=external
+
+borg create -v --stats  \
+        $REPOSITORY::$1_$(date +%F_%H-%M) \
+        /var/lib/libvirt/images/$1.qcow2  \
+        /root/backups/vm_meta
+
+echo "Pivoting base image back to original"
+virsh blockcommit $1 vda --pivot --base=/var/lib/libvirt/images/$1.qcow2
+
+echo "Removing snapshot image"
+rm /var/lib/libvirt/images/$1.hotswap.qcow2