What is Ubuntu enterprise cloud?
Solution 1:
Cloud:
A cloud is a group of servers that share resources for virtualization. When you create a new virtual machine it automatically decides on what server to put the VM and what storage to use depending on the resources left.
It can be seen as a storage pool or resource pool.
There is no real point in setting up a cloud on only one server if you don't intend on adding other servers to the cloud. You would lose performance.
Virtual Machine Host:
You would probably be more interested in just setting up a virtual machine host which will use libvirtd for managing your virtual machines and qemu/kvm for the actual virtualization.
Solution 2:
It allows you to use (roughly) the same API and system as Amazon's Elastic Cloud (by way of the Eucalyptus project). It can be useful for compartmentalising your servers - otherwise straight VM's are OK as well.
Services offered include virtual machines which can be spun up/down at will - with the same resource allocation as Amazon, and a separate storage system. If you are considering using Amazon EC2 in the future it would be sensible - otherwise if you will always be a straight VM shop then there is no need.