Use cases for data centers can be as varied as the applications that reside in the data center. To tie together some of the concepts from earlier chapters, we’ll look at examples that demonstrate:
A hierarchical application with a low degree of multitenancy in an orchestrated overlay
A DevOps alternative to overlay orchestration
SDN in a big data application (application-driven network control)
NFV/service chaining both in and outside the data center
The roles played by data center infrastructure can be pure IaaS, PaaS, SaaS, or any combination of these services.
A typical vertical industry service center that primarily provides SaaS services (a data center for specialized information management, for example, medical records management, human resources outsourcing, etc.) might envision several client types, with varying levels of commonality (the variance comes in how they might connect to the outside).
Their client’s commonality comes from the fact that all assume some level of public/Internet access to the SaaS service and that access will always traverse an ADC (the ADC does some fundamental security, and load balancing).
The operator’s primary concerns are scale, ease of operations, and security. In the case of the latter, all the systems are to be protected from worms, viruses, malware, and other types of intrusion.