Warnings were issued for a number of different issues. Most were due to the VM's inability to acquire a new IP address in the new environment. A VM reporting changes in memory configuration or CPU speed also resulted in a warning. In other warning cases, some functionality was lost, such as the ability to pause or unpause a running VM in its new environment.
"In some situations with warnings, things should be OK, but it could require some manual intervention, and manual intervention is not optimum," Kamhout said.
No one hypervisor handily beat the others in terms of supporting OVF. All had blind spots. "It really seems like a pretty wide variety of capabilities at the hypervisor level," Kamhout said.
Although the study did not test how well the VM OSes fared per se, it found that Windows 2008 was able to work the most easily across all the different hypervisors, while CentOS required the most additional work. "Windows 2008 was the most forgiving of changes," Kamhout said,
ODCA, however, is confident that hypervisor managers will use the study to further refine their products. "This is a baseline test," Kamhout said, adding that "the solution providers have [shown] a strong interest in fixing the gaps pretty quickly."
The Open Data Center Alliance is a consortium of companies interested in better defining long-term data center requirements, and includes members such as BMW, Capgemini, China Unicom, Deutsche Bank, JPMorgan Chase, Lockheed Martin, Marriott, Disney, and UBS. Intel serves as technical advisor to the Alliance.
The researchers will further discuss this work at ODCA's Forecast cloud computing conference, being held in San Francisco on June 17.