If one were to define cloud in a single word in the context of what came before—grid computing—the term “outsourcing” might first spring to mind. In cloud, it’s the outsourcing of resources and most often of management complexities, thus while the two are closely related in the abstract, they are also directly opposites in some ways. As grid luminary Ian Foster noted in an excellent interview from Steven Mounsey, “the cloud is about outsourcing, the grid is about federation.” This one spartan statement is loaded with meaning about collaboration, enterprise and academia differences, and the possibilities offered by cloud—not to mention what might be lost.
According to Ian Foster, “a grid makes the most of what its users contribute to it, whereas cloud computing is designed from the outset as a service.” In other words, despite the fact that Foster sees great promise for cloud, the underlying system of sharing, provisioning, and management is completely different. As Foster notes, “The aspect of cloud is about providing the reliable sources of computing that were perhaps lacking in the early days of grid computing. We ended up building our own supplies of storage, computing and other things, but we could never operated those as efficiently as a company like Amazon could do”
Foster also discussed public clouds by attacking the 800-pound gorilla in the room–namely Amazon’s EC2. The deciding factor in any decision to expand out to such a resource is, of course, the interconnect versus compute punch needed. Foster says, “The nodes offered by EC2 are of a good standard but that they’re not well interconnected. “If you’re running an application that requires a high-speed interconnect, it’s not going to run well on a service like Amazon’s. On the other hand, it the application is fairly compute-intensive and there isn’t communications between processors, then these sorts of systems work quite efficiently.
Many of Foster’s comments are shaded by the responses of other key players in HPC and cloud, including Jason Stowe of Cycle Computing, Songnian Zhou of Platform Computing, and Christian Tanasescu of SGI. Rather than just serving as a deep overview piece about the current state of HPC and cloud, this also provides some insight from leading members of the community speaking about the broader context of many of the issues we discuss here.