Cloud applications typically involve several components that interact through an API that exchanges data in either the XML or JavaScript Object Notation (JSON) formats. This article from Shalini Gilra, Prem Prakash and Tom Tuohy discusses techniques for using the open source tool Apache JMeter to perform functional, performance and reliability testing of Cloud applications that use RESTful web APIs and JSON.
As multitenancy is an important feature of Cloud application, this article shows how to incorporate data separation and data retrieval programmatically to ensure data integrity. It explains how to write effective JMeter test scripts that facilitate the maintenance, re-usability, and modularity. You will also learn how to use configuration and properties files so that the same scripts can run in multiple environments. The article also explains how to etend functional JMeter scripts for performance and reliability testing
Read the complete article on http://www.ibm.com/developerworks/cloud/library/cl-jmeter-restful/index.html