After introducing the Logical Datacenter Designer toolbox and the prototypes that it provides, we presented a sample logical datacenter diagram based on a real-life deployment configuration that one of the authors has encountered. That was to get you used to the idea of logical datacenter modeling and the style of the diagrams.
We then turned our attention to the StockBroker running example as a vehicle for specifying a logical datacenter in more detail.
Our original application design involved a number of applications, but some—such as the MarketMaker and StockMarket—we regarded as external and outside of our core design. You might wonder, therefore, why we modeled servers to host those applications in the logical datacenter. In part, we did that because the datacenter is defined by the operations team, which has less concern about which applications will be developed in house and which externally. If the external components are to be hosted in house (even if not developed in house), then operations will need to specify servers to host them. Otherwise, operations may need to model the characteristics of the third-party remote servers and zones on which they will be hosted, or maybe even specify to the third parties the characteristics that those servers and zones should exhibit—as part of the service-level agreement.
You saw how the settings and constraints for any server or endpoint may be accessed and manipulated, and you looked at some examples (although coverage of the full range of settings and constraints for every server type was not practical here).
Finally, you learned how to add your own prototypes to the toolbox, and how to share your prototypes in a team environment.
In Chapter 4, we'll pull together the application design from Chapter 2 and the logical datacenter design from this chapter by mapping the applications onto the datacenter.