diff --git a/multi-node-aio/variables.sh b/multi-node-aio/variables.sh
index 66368d6c..32155574 100755
--- a/multi-node-aio/variables.sh
+++ b/multi-node-aio/variables.sh
@@ -1,44 +1,44 @@
 # Variables used by multi-node-aio
 # Network subnet used for all the virtual machines
-NETWORK_BASE=172.29
+NETWORK_BASE="${NETWORK_BASE:-172.29}"
 # DNS used throughout the deploy
 #DNS_NAMESERVER=$(cat /etc/resolv.conf | grep -m 1 "nameserver" | sed "s/nameserver //")
-DNS_NAMESERVER=8.8.8.8
+DNS_NAMESERVER="${DNS_NAMESERVER:-8.8.8.8}"
 
 # By default AIO deploy overrides apt-sources, if things like a local mirror are already
 # set up then this script will override these. This option allows for the override to be
 # disabled.
-OVERRIDE_SOURCES=true
+OVERRIDE_SOURCES="${OVERRIDE_SOURCES:-true}"
 
 # What branch of Openstack-Ansible are we deploying from
-OSA_BRANCH=master
+OSA_BRANCH="${OSA_BRANCH:-master}"
 
 # What is the default disk device name
-DEVICE_NAME=vda
+DEVICE_NAME="${DEVICE_NAME:-vda}"
 
 # What default network device should we use for Cobbler
-DEFAULT_NETWORK=eth0
+DEFAULT_NETWORK="${DEFAULT_NETWORK:-eth0}"
 
 # What is the default virtual machine disk size in GB
-VM_DISK_SIZE=252
+VM_DISK_SIZE="${VM_DISK_SIZE:-252}"
 
 # Do we want to do all the required host setup
-SETUP_HOST=true
+SETUP_HOST="${SETUP_HOST:-true}"
 
 # Do we want to do disk partitioning or is there a partition ready to use
-PARTITION_HOST=true
+PARTITION_HOST="${PARTITION_HOST:-true}"
 
 # Do we want to set up networking on the host for Virsh
-SETUP_VIRSH_NET=true
+SETUP_VIRSH_NET="${SETUP_VIRSH_NET:-true}"
 
 # When the virtual machines are re-kicked do we format them
-VM_IMAGE_CREATE=true
+VM_IMAGE_CREATE="${VM_IMAGE_CREATE:-true}"
 
 # Should we run the deploy Openstack-Ansible script at the end of the build script
-DEPLOY_OSA=true
+DEPLOY_OSA="${DEPLOY_OSA:-true}"
 
 # Should we pre-configure the environment before we deploy OpenStack-Ansible
-PRE_CONFIG_OSA=true
+PRE_CONFIG_OSA="${PRE_CONFIG_OSA:-true}"
 
 # Should we run the final deploy of OpenStack-Ansible
-RUN_OSA=true
+RUN_OSA="${RUN_OSA:-true}"