Deployment Models, Service Models, and Cloud Characteristics Review

Learning outcomes

By the end of this lesson, the learner can:

1. Explain the main cloud deployment models: cloud, private cloud/on-premises, and hybrid.
2. Recognize the common service-model idea of IaaS, PaaS, and SaaS at a high level.
3. Explain key cloud characteristics such as agility, elasticity, and pay-as-you-go pricing.
4. Connect AWS services you already learned to these broader models.

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What this review covers

This lesson answers three questions:

1. Where does the workload run?
2. How much of the stack do I manage?
3. What makes cloud different from traditional infrastructure?

AWS says cloud computing provides the ability to avoid undifferentiated work such as procurement, maintenance, and capacity planning, and different deployment models provide different levels of control, flexibility, and management. (AWS Documentation)

A simple memory rule is:

• deployment model = where the resources live
• service model = how much AWS or the provider manages for you
• cloud characteristics = what makes cloud valuable in practice

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1) Deployment models

A) Cloud

AWS says a cloud-based application is fully deployed in the cloud, and all parts of the application run in the cloud. AWS also notes that cloud-based applications can use either low-level infrastructure pieces or higher-level managed services. (AWS Documentation)

Mental model:

• everything runs in the cloud provider environment

Examples:

• an app built on EC2, RDS, and S3
• an app built on DynamoDB, Lambda, and API Gateway

B) Private cloud / on-premises

AWS says on-premises deployment uses local infrastructure, often with virtualization and resource-management tools, and is sometimes called private cloud. AWS also says on-premises deployment does not provide many of the benefits of cloud computing, though some organizations still choose it for dedicated resources. (AWS Documentation)

Mental model:

• the infrastructure stays in the organization's own environment

C) Hybrid

AWS says hybrid deployment connects cloud-based resources with existing resources that are not located in the cloud, and the most common example is connecting the cloud with on-premises infrastructure. (AWS Documentation)

Mental model:

• part of the system is in the cloud
• part of the system is somewhere else, often on-premises

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2) Service models

AWS's overview pages emphasize that cloud applications can be built on lower-level infrastructure pieces or higher-level managed services. (AWS Documentation)

A simple way to think about service models is:

A) IaaS: Infrastructure as a Service

This is the "more control" model.

You manage more of the software stack, while the provider gives you the infrastructure building blocks.

Examples from your course:

• EC2
• EBS
• networking building blocks around compute

Mental model:

• "I get the server and infrastructure building blocks, and I manage more of the rest."

B) PaaS: Platform as a Service

This is the "managed platform" model.

You focus more on the application and less on the underlying infrastructure.

Examples from your course:

• Lightsail as a simplified app platform
• ECS on Fargate as a managed container execution platform
• RDS as a managed database platform

Mental model:

• "I focus more on the app or data, and AWS manages more underneath."

C) SaaS: Software as a Service

This is the "finished software" model.

The provider runs the application, and the user mainly consumes it rather than building the underlying platform.

AWS Marketplace documentation, for example, describes SaaS products as software you subscribe to but access in the software seller's environment. (AWS Documentation)

Mental model:

• "I use the software, I do not build the whole platform underneath it."

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3) Cloud characteristics that matter most

AWS's cloud-computing advantages page lists six major advantages of cloud computing:

• trade fixed expense for variable expense
• benefit from massive economies of scale
• stop guessing capacity
• increase speed and agility
• stop spending money running and maintaining data centers
• go global in minutes. (AWS Documentation)

For this course level, the biggest ones to remember are:

A) Variable expense / pay-as-you-go

AWS says you pay only when you consume computing resources, instead of investing heavily in data centers and servers before you know how you will use them. (AWS Documentation)

B) Agility

AWS says new IT resources are only a click away, which reduces the time to make resources available from weeks to minutes. (AWS Documentation)

C) Elastic capacity

AWS says cloud computing helps you stop guessing capacity, because you can access as much or as little capacity as needed and scale up and down as required. (AWS Documentation)

D) Global reach

AWS says you can deploy applications in multiple Regions around the world in minutes. (AWS Documentation)

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4) How this connects to AWS services you already learned

This lesson becomes easier when you map the abstract models to real AWS services:

• EC2 fits the more infrastructure-heavy side of cloud usage, closer to the IaaS mental model.
• RDS shifts more responsibility to AWS, closer to the managed-platform mental model.
• ECS on Fargate is a strong example of a managed platform approach for containers.
• Lightsail is a simplified bundled platform experience.
• SaaS is usually outside "you building the infrastructure" and closer to consuming finished software.

Key takeaway:

• the models are not just theory
• they help you understand why some AWS services feel low-level and others feel more managed

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5) Deployment model vs service model

Learners often confuse these.

Here is the clean difference:

• deployment model asks: where is the workload running? Example: cloud, on-premises/private cloud, hybrid. (AWS Documentation)

• service model asks: how much of the stack do I manage? Example: infrastructure-heavy, managed platform, or finished software.

So:

• you can have a cloud deployment
• and inside that, choose a more IaaS-like or more PaaS-like service

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6) A simple comparison table

CSV version:

Concept,Mental model
Cloud deployment,Everything runs in the cloud
Private cloud / on-premises,Runs in the organization's own environment
Hybrid deployment,Split between cloud and non-cloud resources
IaaS,More infrastructure control
PaaS,More managed platform
SaaS,Finished software you consume
Agility,Move fast
Elasticity,Grow and shrink as needed
Pay-as-you-go,Variable expense instead of large upfront hardware cost

This table is based on AWS's deployment-model overview and six-advantages overview. (AWS Documentation)

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Micro-activity 1

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Micro-activity 2

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Summary

AWS says cloud computing helps organizations avoid undifferentiated work such as procurement, maintenance, and capacity planning, and offers different deployment models with different levels of control and management. AWS also highlights variable pricing, agility, elasticity, and global reach as core cloud advantages. (AWS Documentation)

The most important distinctions are:

• cloud / private / hybrid = where workloads live
• IaaS / PaaS / SaaS = how much of the stack you manage
• agility / elasticity / pay-as-you-go = why cloud is attractive in practice

The simplest memory rule is:

• deployment model = where
• service model = how managed
• cloud characteristics = why it is valuable

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Quiz 5.3

Reflection questions

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Answer key

A1: A. AWS says a cloud-based application is fully deployed in the cloud. (AWS Documentation)

A2: B. AWS says hybrid deployment connects cloud-based resources with non-cloud resources, most commonly on-premises infrastructure. (AWS Documentation)

A3: B. IaaS is the more infrastructure-control side of cloud usage.

A4: IaaS gives you more direct infrastructure control, while PaaS gives you a more managed platform so you can focus more on the application.

A5: B. SaaS means you consume software running in the provider's environment. (AWS Documentation)

A6: A. AWS's "Six advantages of cloud computing" page lists that advantage explicitly. (AWS Documentation)

A7: Because you avoid large upfront hardware spending and instead pay for what you actually use. AWS states this as trading fixed expense for variable expense. (AWS Documentation)

A8: B. AWS describes agility as reducing resource-availability time from weeks to minutes. (AWS Documentation)

A9: Hybrid deployment. (AWS Documentation)

A10: Deployment model = where the workload lives. Service model = how much of the stack you manage.

Next lesson

Lesson 5.4: Cloud Concepts Review Quiz