How do I?

openstack loadbalancer create --vip-network-id VLAN164 --name my-lb
openstack loadbalancer listener create --name listen-http --protocol HTTP --protocol-port 80 my-lb
openstack loadbalancer listener create --name listen-https --protocol HTTPS --protocol-port 443 my-lb
openstack loadbalancer pool create --name pool-http --lb-algorithm ROUND_ROBIN --listener pool-http --protocol HTTP
openstack loadbalancer pool create --name pool-https --lb-algorithm ROUND_ROBIN --listener pool-https --protocol HTTPS

cat virtual_hosts.txt | while read host;
do 
  openstack loadbalancer member create --subnet-id 9f9a73fd-2a98-4cfb-ac43-645b119e0135 --address $host --protocol-port 80 pool-http
  openstack loadbalancer member create --subnet-id 9f9a73fd-2a98-4cfb-ac43-645b119e0135 --address $host --protocol-port 443 pool-https
done

A free IP is taken from VLAN164 and an HAProxy instance listens for HTTP and HTTPS traffic on ports 80, 443. Any traffic to those ports will be sent to a health (responding) virtual instance on the subnet id 9f9a73fd-2a98-4cfb-ac43-645b119e0135.