Add a script to allocate VIPs in PS6

This eneusres that these IP addresses don't get used by OpenStack and
the relevant VIPs can be utilised and hence don't have conflicts

openstack/tools/allocate_vips.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+
+# Allocate the last 20 IP addresses, which could be considered for
+# VIPs in OpenStack
+
+source ~/novarc
+num_vips=20
+subnet="subnet_${OS_USERNAME}-psd"
+
+cidr=$(openstack subnet show ${subnet} -c cidr -f value 2>/dev/null)
+
+net_end=$(awk -F'.' '/HostMax/{print $NF}' <<<$(ipcalc -b $cidr))
+
+net_end_suffix=${net_end##*\.}
+
+vip_start_suffix=$((net_end_suffix - ${num_vips} + 1))
+net_pre=$(echo $cidr| sed -r 's/([0-9]+\.[0-9]+\.[0-9]+).+/\1/g')
+
+j=1
+
+for i in $(seq ${vip_start_suffix} ${net_end_suffix})
+do
+    openstack port create --network net_${OS_USERNAME}-psd \
+        --fixed-ip subnet=subnet_${OS_USERNAME}-psd,ip-address=${net_pre}.$i \
+        --disable --os-cloud ps6 ps6-vip-ip$( printf "%02d" $j )
+    ((j++))
+done