"The biggest challenge is that there's so much happening in the cloud that users are so busy figuring out how best to use cloud that lock-in is still not a big concern for them," says David Lutterkort, principal software engineer at Red Hat and chair of the Apache Deltacloud project. "It's not that high on peoples' lists yet."

Deltacloud is an API that abstracts differences between clouds, enabling management of resources in different IaaS clouds using a single API. It can essentially be implemented as a wrapper around a large number of clouds, freeing users of cloud computing from dealing with the particulars of each cloud's API.

Standards bodies have also coalesced to create open and interoperable standards. In 2009, leading standards development organizations (SDOs) to form , intended to coordinate the work of the various SDOs developing cloud standards. Members include the Cloud Security Alliance, Cloud Standards Customer Council, Distributed Management Task Force (DMTF), the European Telecommunications Standards Institute (ETSI), the National Institute of Standards and Technology (NIST), Open Grid Forum (OGF), Object Management Group (OMG), Open Cloud Consortium (OCC), Organization for the Advancement of Structured Information and Standards (OASIS), Storage Networking Industry Association (SNIA), The Open Group, Association for Retail Technology Standards (ARTS) and TM Forum.

Lutterkort is also a board member of the DMTF, which, among other things, is working on a standard called the Cloud Infrastructure Management Interface (CIMI), which would create a standard API that any cloud could use.

is another forward-looking open source project, driven by Red Hat, that essentially seeks to build an open source cloud broker. A stand-alone project, Aeolus offers a single, consistent set of tools to build and manage organized groups of virtual machines across clouds. It consists of the following: