PE2-6.3 Cloud Architecture & Service Models
You can compare monolithic with microservice architecture, distinguish SaaS, PaaS and IaaS by their features, benefits, challenges and risks, and choose among public, private, community and hybrid deployment models.
The service models form a ladder of how much you manage versus how much you control, and the right way to remember them is by where the boundary of your responsibility falls. Deployment models answer a different question entirely — who else is on the hardware — and conflating the two axes is the standard confusion. Microservices are presented as the cloud-native counterpart to monoliths, and the honest reading is that they trade deployment simplicity for operational complexity.
Work through these
Basic cloud architecture
How a cloud application is put together, in outline. It is the frame for the service models below.
Monolithic and microservice architecture
One deployable unit against many small ones, which is the structural choice that most affects how a system is operated. Neither is right in general, and knowing why is the content.
SaaS: features, benefits, challenges and risks
Software delivered as a service, with the trade stated fully. You give up control of the software in exchange for never operating it.
PaaS: features, benefits, challenges and risks
A platform to deploy onto, which sits between the two. It removes the operating system from your concerns and constrains what you can build.
IaaS: features, benefits, challenges and risks
Raw infrastructure, which gives the most control and the most work. Comparing the three on what you manage is the exercise of this topic.
Public and private clouds
Who the infrastructure is shared with, in the two basic cases. The decision is usually driven by regulation rather than technology.
Community and hybrid clouds
The two middle cases, one shared between similar organisations and one spanning both. The hybrid case is what most large organisations actually run.
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