Describe cloud models
📘Microsoft Certified: Azure Fundamentals (AZ-900)
What is Public Cloud?
A cloud model where resources (such as compute, storage, and networking) are owned and operated by a cloud provider like Microsoft Azure.
Multiple customers share the cloud provider’s infrastructure (but data remains isolated and secure).
Best Use Cases for Public Cloud
1. Startups or New Projects
When organizations need quick deployment without buying hardware.
2. Applications with Unpredictable or Highly Changing Workloads
Azure can automatically scale up or down based on demand.
3. Development and Testing Environments
Developers can easily create and delete environments without worrying about local servers.
4. SaaS Services
Email, productivity apps, and collaboration tools hosted on cloud platforms.
5. Organizations That Want to Reduce Capital Expenses
No need to purchase servers, storage, or networking equipment.
6. Global Availability Requirements
Applications that need to run in multiple geographical regions.
Why Choose Public Cloud?
- Fast setup
- Automatic scaling
- Pay-as-you-go pricing
- Global infrastructure
- No hardware management
Exam Tip:
Public cloud = cost-effective, scalable, quick to deploy, no on-premises hardware required.
2. Private Cloud Use Cases
What is Private Cloud?
A cloud environment dedicated to one organization.
It can be hosted:
- on the organization’s own datacenter (on-premises), or
- by a third-party provider, but still dedicated only to one organization.
Best Use Cases for Private Cloud
1. Organizations with Strict Security or Compliance Requirements
Industries such as finance, healthcare, or government.
2. Workloads Requiring Full Control Over the Environment
Admins manage security, networking, storage, and compute.
3. Highly Customized Applications
Some applications need very specific networking, storage, or security configurations.
4. Data Sovereignty Requirements
When data must remain inside the organization’s physical location.
5. Predictable and Constant Workloads
When resource usage does not change much, owning infrastructure can be cost-effective.
6. Legacy Applications
Applications not designed for public cloud.
Why Choose Private Cloud?
- Highest level of control
- Strict data governance
- Fully customized environment
- Dedicated security and compliance controls
Exam Tip:
Private cloud = highest control + strict security + dedicated environment.
3. Hybrid Cloud Use Cases
What is Hybrid Cloud?
A combination of public cloud and private (or on-premises) cloud working together.
Data and applications can move between both environments.
Best Use Cases for Hybrid Cloud
1. Organizations That Want to Keep Some Data On-Premises
Example: sensitive databases stored privately, while applications run in Azure.
2. Gradual Cloud Migration (Move to Cloud Step-by-Step)
Organizations can migrate workloads over time instead of moving everything at once.
3. Applications That Need to Run in Both Environments
Some parts run on local servers, others run in Azure.
4. Disaster Recovery and Backup Solutions
Using Azure as a secondary site while primary systems stay on-premises.
5. Burst Workloads (Cloud Bursting)
When local servers reach capacity, extra workload is sent to Azure temporarily.
6. Compliance Requirements That Prevent Full Cloud Adoption
Store sensitive data locally but use Azure for scalable processing.
Why Choose Hybrid Cloud?
- Combines control (private cloud) with flexibility (public cloud)
- Supports modern and legacy applications
- Great for backup, disaster recovery, and temporary workloads
Exam Tip:
Hybrid cloud = best of both worlds, partial cloud adoption, data can move between environments.
4. Summary Table for Quick Revision
| Cloud Model | Key Characteristics | Best Use Cases |
|---|---|---|
| Public Cloud | Shared infrastructure, pay-as-you-go, scalable | Development/testing, global apps, variable workloads, startups |
| Private Cloud | Dedicated environment, highest control | Sensitive data, compliance needs, legacy apps, customized workloads |
| Hybrid Cloud | Mix of public and private, flexible | Gradual migration, disaster recovery, sensitive + non-sensitive workloads, cloud bursting |
5. AZ-900 Exam-Focused Guidance
You may be asked questions like:
Which cloud model is best for highly sensitive data?
âž¡ Private Cloud
Which cloud model is best for unpredictable traffic spikes?
âž¡ Public Cloud
Which cloud model supports gradual migration?
âž¡ Hybrid Cloud
Which cloud model offers the lowest upfront cost?
âž¡ Public Cloud
Which cloud model provides the highest level of customization and control?
âž¡ Private Cloud
6. Final Key Points to Remember
- Public cloud = scalability, low cost, no hardware
- Private cloud = control, compliance, dedicated environment
- Hybrid cloud = flexibility, partial on-premises, ideal for migration
Understanding these use cases will help you answer many scenario-based questions in AZ-900.
