diff --git a/cluster/vagrant/config-default.sh b/cluster/vagrant/config-default.sh
index f17e87c68bc..da6d74519f0 100755
--- a/cluster/vagrant/config-default.sh
+++ b/cluster/vagrant/config-default.sh
@@ -21,14 +21,14 @@ NUM_MINIONS=${NUM_MINIONS-"1"}
 export NUM_MINIONS
 
 # The IP of the master
-export MASTER_IP="10.245.1.2"
-export KUBE_MASTER_IP="10.245.1.2"
+export MASTER_IP=${MASTER_IP-"10.245.1.2"}
+export KUBE_MASTER_IP=${MASTER_IP}
 
 export INSTANCE_PREFIX="kubernetes"
 export MASTER_NAME="${INSTANCE_PREFIX}-master"
 
 # Map out the IPs, names and container subnets of each minion
-export MINION_IP_BASE="10.245.1."
+export MINION_IP_BASE=${MINION_IP_BASE-"10.245.1."}
 MINION_CONTAINER_SUBNET_BASE="10.246"
 MASTER_CONTAINER_NETMASK="255.255.255.0"
 MASTER_CONTAINER_ADDR="${MINION_CONTAINER_SUBNET_BASE}.0.1"