First, many open source applications are now available on a Software-as-a-Service (SaaS) basis. For open source project owners, hosting apps in the cloud offers a new revenue stream. And for users, it means access to excellent programs and support without the need to maintain their own hardware or hire additional support personnel.
Also, because these apps are accessed via a browser, they're generally multi-platform and enable more workforce mobilitynot to mention that they usually costs less than proprietary alternatives.
Other open source projects aren't available on an SaaS basis, but their project owners have taken the steps necessary to make them easy to use in the cloud. By making pre-configured images available through Amazon Web Services or other public clouds, these developers are finding a wider audience. And users benefit from easy-to-deploy solutions that offer the other advantages of cloud computing as well.
Finally, some open source developers are contributing to the growth of cloud computing by creating the tools that make cloud computing feasible. They offer infrastructure, middleware and other software that make it easier for companies to develop and run their applications in the cloud.
For this list, we've included open source apps from all three categories. We know that different people have different definitions of cloud computing and may disagree about what constitutes a true cloud app or a true SaaS app. For the purposes of this list, we considered any app available on a hosted or on-demand basis a cloud app. Where possible, we've linked to the pages that describe how the apps can be used in the cloud.
We also know that in some cases the SaaS versions of these apps include proprietary code that isn't in the free, open source versions. As long as the tool had an open source edition with the same essential functionality as the cloud version, we considered it for our list.
As always, feel free to add any apps that you think should be on this list to the comments section below.
5. Pentaho Pentaho's business intelligence suite includes reporting, analysis, dashboards, data integration and data mining modules. The on-demand version also includes "data services ondemand," a thin-client Agile BI data wizard. Operating System: Windows, Linux, OS X.
6. Palo BI Suite The "first open source, software as a service, business intelligence solution," Palo's SaaS edition can help companies reduce their hardware, maintenance and installation costs. It offers planning, analysis and reporting capabilities that are a step up from using a spreadsheet application. Operating System: OS Independent.
7. OpenI OpenI was specifically designed for on-demand and SaaS deployments. It helps users visualize data from OLAP and relational databases through reports and dashboards. Operating System: OS Independent.
10. Cloud.com CloudStack CloudStack makes it possible for enterprises and service providers to build and manage their own clouds. While the community version is completely open source, the enterprise and service provider editions use some proprietary code. Operating System: Linux
11. OpenNebula OpenNebula bills itself as "the open source toolkit for open source computing." It is enterprise-class IaaS software that can handle hundreds of thousands of virtual machines. Operating System: Linux.
12. Eucalyptus Eucalyptus software implements scalable IaaS-style private and hybrid clouds. Community members can also access the Eucalyptus Community Cloud where they can test the software in the cloud. Operating System: Linux.