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These materials are the copyright of John Wiley & Sons, Inc. and any dissemination, distribution, or unauthorized use is strictly prohibited. 18 Platform as a Service For Dummies, Special Edition PaaS and the application lifecycle In PaaS, the application lifecycle from development through testing, staging, and deployment is baked into the platform. The development and runtime platforms are provided as services, so the formal lifecycle of an application is more directly supported. For example, developers and test teams interact with the same hosted application and runtime as the operations people use. One of the impacts of having an abstracted platform is that it supports development to deployment to operation procedures that today are mostly manual, which helps support agile development (discussed in more detail in Chapters 3 and 4). Removing the manual processes enables faster development release cycles, which in turn can support more rigorous methods around quality and continuous integration. PaaS as Middleware in the Cloud Middleware is the glue that helps connect software components and is a critical method of delivering standardized application services, but it can be complicated. When middleware services are hosted, like they are in a PaaS, they can provide a development team with the ability to pre-determine how the organization wants connectivity to happen and how integration between services is handled. IT management can then set the rules upfront about what types of services to use under specific business conditions. For example, an organization may want to mandate the use of a specific database for an application because of the need to have sufficient transaction speed. Because this abstraction of middleware is service based, its Application Programming Interfaces (APIs) are typically well defined, so managing the integration is simplified. You used to have to install resources and interact with them on your machines. Now, those services are managed and made available to you with PaaS. You’ll see some key differences between PaaS and traditional middleware:
These materials are the copyright of John Wiley & Sons, Inc. and any dissemination, distribution, or unauthorized use is strictly prohibited. Chapter 2: Getting into Platform as a Service 19 ✓ Resources aren’t delivered as software in PaaS. Instead, they’re hosted, always-on, on-demand, served up as services. ✓ The scope of where development and delivery can take place in a PaaS is the cloud instead of a single machine or process. ✓ Resources in the data center, now served up by IaaS, are managed by the PaaS for the purposes of supporting applications. It’s not just the machine supporting the application. In fact, Cloud IaaS means infrastructure is available programmatically, so middleware can now be expanded to take direct advantage of it. Without infrastructure constraints, you can deliver and update software continuously. This process is harder in older-generation middleware with hardcoded endpoints. ✓ Middleware and services have no installation and configuration because they’re an integral part of the PaaS platform. Different Types of PaaS All PaaS environments aren’t the same. You need to consider several different approaches to PaaS. PaaS anchored to a SaaS environment Some SaaS platforms are becoming core business services for many companies. Offerings, such as Workday, SugarCRM, and Salesforce.com, are replacing traditional on-premises systems of record. Some of these SaaS vendors focus on expanding their offerings to the platform level. Salesforce.com, for example, provides a PaaS platform called Force.com that exposes the native Salesforce.com APIs, development tools, and middleware so it becomes a platform that software developers can use to build new applications on top of. This approach can be sensible if a company wishes to extend the capabilities of their Salesforce.com (or other kinds of SaaS) applications.
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