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Cloud bursting

Cloud bursting as a concept has been spoken of since the inception of the public cloud. Let's take a simple example to elucidate the need for cloud bursting. Say you run an electronic commerce site and on a festive day or when there is a sale, you get huge bursts of traffic for an otherwise, predictable traffic website.

In this case, one would design the environment to serve the predictable traffic and use the public cloud in order to take over the extra connections.

A few points to note while designing an environment capable of bursting are:

Stateless and horizontably scalable tier
Network connectivity and redirection

In the preceding diagram, we can see that the Predicted Traffic is handled by the application components in the private cloud, however the Bursty Traffic is handled by a part of the application that is spun off in the public cloud.

While in theory, any tier can be bursted, normally only the web or the application tier (or a combination of the two) are considered for bursting in the real world.

If the application is designed appropriately, the scalability of the application can be near infinite with the public cloud being used only for the period of the burst, and the only prerequisite would be having network connectivity in place.

While it is not shown in the preceding diagram, in some cases, some data also needs to be copied between the data center and the public cloud for the tier to work.