Chat application on Azure platform

OData support
Dr. Kővári Bence András
Department of Automation and Applied Informatics

In our days public clouds are getting more common, thanks to the comfort they

provide by taking over the management and maintenance tasks of the complex

infrastructure, which is necessary to operate an IT service. Furthermore, in certain

execution modes – particularly on the PaaS or Platform as a Service level – they also

provide a number of useful features that can help building efficient and scalable


However, to be able to fully utilize the advantages of the PaaS environment, an

application should also be correctly prepared for its special nature. There are cases when

an application which could be easily implemented in a regular environment needs to be

redesigned or extended significantly to properly fit in the cloud.

In this thesis I will describe the most important steps of building a web based,

real-time chat application which can run on Microsoft's Azure platform, utilizing the

advantages of the PaaS concept.

In this case the difficulties are caused by the default Round-Robin behavior of

the built-in Azure load balancer, which eliminates any possibility of using the Reverse

AJAX technique, which could deliver real-time notifications to a web based client.

To get around the issue I employed an Azure feature called InstanceInput

endpoint, which allowed me to implement some sort of affinity (or sticky) load

balancing, bypassing the default load balancer.

In this paper I will first briefly review the utilized technologies, and then show

the detailed architecture of the complete program and parts of its implementation.

Finally, I will examine the scalability of the given application by taking it under a

simpler load test.


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