You have a Cloud, now what? In the last few years we have seen many presentations focused on how to build IaaS clouds. However very few, if any, actually tackle the issue of how to use a Cloud once you are done building it. In this presentation will look at key open source software that form the cloud ecosystem and are used to make use of a working cloud. Specifically we will review software like apache libcloud, jclouds, delatcloud, hadoop. We will also review the state of configuration management systems and their support for IaaS cloud software. We will go beyond talking about Cloud APIs and focus on API wrappers and how they are used to automate provisioning of virtual infrastructure within IaaS deployments. These software typically are not key to building a cloud but are used to make use of a working cloud. The higher level software are key to build applications, workflows or higher level abstractions like PaaS. We will go beyond talking about Cloud APIs and focus on API wrappers and how they are used to automate provisioning of virtual infrastructure within IaaS deployments. Specifically we will discuss API wrappers within the apache software foundation: libcloud, jclouds and delatcloud. To complement this wrappers we will also discuss OCCI and CIMI standard interfaces to IaaS systems (CloudStack, Opennebula and OpenStack). We will also discuss the state of configuration management systems (Chef, Puppet, Salt and Ansible) and their support/use for IaaS cloud software. These systems are of course used to build clouds but can also be used to provision virtual infrastructure within these clouds, the latter will be our focus. To illustrate our point we will describe several scenarios where we use Chef and SaltStack to provision a hadoop cluster, an elasticsearch cluster and a RiakCS cluster on a CloudStack based cloud. People attending the talk will see how the open source ecosystem build around IaaS solutions is used to deploy applications and workloads that they need. They will see how a IaaS gets them to the point of thinking about the applications and a faster provisioning time for their workloads instead of thinking of just building a IaaS