Open Stack

Hi, 
 
We are a small shop and have our customers in host our solution in their data centers. We plan to use OpenStack to automate our delivery but are challenged the minimum hardware required to have an HA system. Most of our customers have a 2-4 servers in and a dedicated HA is practical for us. Hence, we plan to deploy all-in-one with share database in production. Any suggestion would be of great help. 
 
Thanks! 
Deb