The hype about cloud computing has gotten so loud that Gartner Group used Cloud as the lead in its hype-parazzi special report Hype Cycle 2009. The sharply sloping graph in the report places cloud, along with e-book readers, wireless power and social software suites, at or near the "Peak of Inflated Expectations," preparing for a dive into the "Trough of Disillusionment." One thing that may drive it into that trough - other than the unrealistic projections by some providers of cost-savings and easy capacity planning - is the difficulty in getting certain applications to run on it effectively, according to analysts and vendors selling technology to help bridge the gap.
What are the difficulties? Here's a look at five key hurdles.
1. Today's clouds are not alike No one "cloud platform" exists - each is different, meaning the specific migration, support, cost and capacity issues vary from vendor to vendor. And moving a legacy application to the cloud means taking a proven quantity in a known environment and moving it to a new environment that will make almost everything about it different, according to Bernard Golden, CEO at HyperStratus, and CIO.com blogger.
"Legacy applications come with a lot of integration with your other systems, and usually they had to be done fast, so you have a lot of direct database calls from one application to another and that kind of thing that may not work when one endpoint is outside the perimeter," according to Golden.
"There's the tiny straw issue, too; there is an order of magnitude more bandwidth available inside the data center than outside it. And you have to decide whether it's important that you manage everything from one pane of glass, because the management tools are not up to doing that with cloud and legacy applications yet," Golden says. "There are a lot of basic technical issues that are often not addressed."
2. Security worries Security gets top billing as a risk of cloud computing because the idea is new and the locks aren't as fully tested as those on legacy applications. At least as big an issue for many companies is knowing who is using the applications or accessing the data, whether they have permission to do so or not, according to Chris Wolf, infrastructure analyst at The Burton Group.
"For enterprises that have security or compliance concerns, multitenant cloud infrastructures are just non-starters right now, because the tools to monitor or control that has not been addressed yet," he says.
Single-tenant clouds - that is, cloud platforms a company owns and manages itself - only solve part of that issue. Being able to physically limit access to the cloud by controlling the rest of the IT infrastructure makes the contained cloud safer, but still doesn't provide the detailed audit trail many companies need to comply with financial or privacy regulations, Wolf says.
3. Licensing and interoperability concerns Legacy applications are supposed to be the creaky inflexible problem when it comes to migration, but neither major software vendors nor cloud providers are making the migration any easier, Golden says.
While most legacy applications have been upgraded from the homegrown, no-public-standards era of corporate computing, most are built with databases, communications or data-translation modules and other commercially-licensed technology. That means vendors like Oracle, Siebel, SAP and others would have to change their licensing to support "three weeks running on three servers, then one week per month expanding to ten and only paying for the capacity you use," Golden says. "Most licenses are still tied to one physical box, although Oracle has made some movements in this direction.
Legacy apps typically also don't typically support the newest technology except in the user interfaces that aren't part of their cores - exactly the technologies on which cloud platforms are built. Microsoft Azure is based on its .Net programming architecture, which most legacy apps are not. Google's App Engine is designed to support software written in Python - a Web-friendly language popular with developers of PHP-based software running on Web servers. Salesforce.com has a proprietary application and data structure.