New Integration Scenarios
Before the cloud model, we had to stitch and tie local systems together. With the shift to a cloud model is on the anvil, we now have to connect local application to the cloud, and we also have to connect cloud application to each other, which add new permutations to the complex integration channel matrix.
It is unlikely that everything will move to a cloud model all at once, so even the simplest scenarios require some form of local / remote integration. It is also likely that we will have applications that never leave the building, due to regulatory constraints like HIPPA, GLBA, and general security issues. All of this means integration must criss-cross firewalls somewhere.
Cloud Integration Scenarios
With a Public Cloud
Two different application are hosted in a cloud. The role of the cloud integration middleware (say cloud-based ESB or Internet Service Bus (ISB)) is to seamlessly enable these applications to talk to each other. The possible sub-scenarios include these application by two different companies. They may live in a single physical server but run on different virtual machines.
Homogeneous Clouds (1)
The application to be integrated are posited in two geographically separated cloud infrastructures. The integration middleware can be in cloud 1 or 2 or in a separate cloud.
There is a need for data and protocol transformation and they get done by ISB. The approach is more or less compatible to enterprise application integration procedure.
Homogeneous Clouds (2)
One application is in public cloud and the other application is private cloud. As described above, this is the currently dominating scene for cloud integration.
Cloud Computing Principles and Paradigms by Rajkumar Buyya, James Broberg and Andrzej Goscinski (c)2011
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