The Quality Attibutes and Architectural Tactics of Amazon Web Services (AWS)

Software architecture plays a critical role in ensuring the quality attributes of a software system (i.e. security, performance, availability, usability, and maintainability). With the advent of cloud computing, popular software architectures are changing. An important change is that some aspects of some quality attributes are now implemented in the cloud software. Architecture elements called tactics (i.e. design decisions that affect the achievement of quality attributes) are built to address the quality attributes of a software architecture. The implementation of a software application using components from a commercial cloud computing platform inherits the quality aspects of the tactics used as part of the implementation of the cloud components, freeing application developers from worrying as much about the quality attributes. We investigated components of the cloud service Amazon Web Services (AWS) and found implementations of key elements of several quality attributes. Furthermore, we identified existing and new tactics used in AWS components to address these quality attributes. In particular, we identified five common quality attributes implemented in AWS components, along with associated tactics: Reliability, Scalability, Performance, Availability, and Security. Most of the tactics are modifications of existing tactics; but several tactics in Security are new. This illustrates the rapid change in the area of security. Opportunities for additional research include expanded studies of tactics in cloud services, and organizing and cataloguing of new tactics.