☁️ Day 2 of Learning Cloud Computing: Cloud Deployment Models - Public, Private, Hybrid & Cross Cloud

In my previous article, I explained what cloud computing is, along with concepts such as AWS, virtual machines, containers, IaaS, PaaS, and SaaS.

When I started learning cloud computing, I understood what cloud computing meant, but one question was still confusing me:

Where does the cloud infrastructure actually live, and who manages it?

This is where Cloud Deployment Models come in.

While learning this topic, I came across four important models:

1. Public Cloud
2. Private Cloud
3. Hybrid Cloud
4. Multi-Cloud / Cross-Cloud

I found these concepts much easier to understand when I stopped trying to memorize their definitions and started thinking about where the infrastructure is located and who manages it.

So, in this article, I'm sharing my understanding of these deployment models in a simple way.

☁️What is a Cloud Deployment Model?

A cloud deployment model basically tells us:

Where is the IT infrastructure physically located, and who manages it?

For example, is the infrastructure:

Inside a cloud provider's data center?
Inside the company's own data center?
Or a combination of both?

Let's understand each model one by one.

1️⃣ Public Cloud

Let's start with the one we usually hear about first: Public Cloud.

What is it?

In a public cloud, the infrastructure such as servers, databases and networking is provided through the cloud service provider's infrastructure.

Some examples of cloud service providers are:

• AWS
• Microsoft Azure
• Google Cloud

The important point is that the cloud provider owns and manages the underlying infrastructure.

Who manages it?

The Cloud Service Provider (CSP) manages the underlying infrastructure.

For example:

AWS manages the physical infrastructure behind AWS services.

As a customer, we use the cloud resources according to our requirements.

🏠 The easiest analogy I used to understand Public Cloud

Imagine you want to live in an apartment.

You don't build the apartment yourself.

The landlord takes care of the building and its maintenance.

You simply rent the apartment and use it.

I think of public cloud in a similar way:

The cloud provider owns the infrastructure, and we use/rent the resources we need.

This is one reason public cloud is very useful for startups and businesses that don't want to purchase and maintain their own physical servers.

2️⃣ Private Cloud

Now let's move to the opposite side.

What is a Private Cloud?

A private cloud is a cloud environment dedicated to one organization.

Here, the infrastructure is not being used as a general public-cloud environment by many different customers.

The organization has much more control over its environment.

Who manages it?

The organization's own IT team can manage the infrastructure, although management can also be handled by a provider depending on the setup.

🏠 The easiest analogy: Your Own House

Think about owning your own house.

You have much more control.

You decide:

How things are arranged
Who can enter
What changes should be made
How the house should be maintained

But there is also a disadvantage.

You have to pay for everything yourself:

• Electricity
• Plumbing
• Repairs
• Maintenance

That's how I remember the basic idea of a private cloud:

More control, but also more responsibility.

One technology that can be used to build private-cloud environments is OpenStack.

3️⃣ Hybrid Cloud

This one became much easier for me once I understood the first two.

Hybrid Cloud = Private Cloud + Public Cloud

So instead of choosing only one environment, an organization uses both.

For example:

Private Cloud + Public Cloud

But why would a company want to do this?

Imagine a company has some sensitive data that it wants to keep in its private environment.

At the same time, it may need extra computing power when there is heavy processing or a sudden increase in traffic.

Instead of buying a lot of extra hardware, the company can use the public cloud for those additional workloads.

🔗 How do Private and Public Clouds communicate?

This is an important part of hybrid cloud.

The two environments need to be connected.

They can communicate using something like:

VPN (Virtual Private Network)
A dedicated private connection, such as AWS Direct Connect

The idea is:

Private Cloud
      ↕
 Secure Connection
      ↕
Public Cloud

So the two environments can work together as one connected system.

🚗 The analogy that helped me understand Hybrid Cloud

Imagine you have some original and sensitive documents stored safely at your home.

Your home represents the private cloud.

Now suppose your office needs copies of those documents, and you need to send them securely.

You use a secure, protected vehicle to transport the copies.

The office represents the public cloud, and the secure vehicle represents the VPN/private connection.

The idea is:

Keep the sensitive information in your private environment, but use the public environment when you need additional resources.

That's the basic idea behind hybrid cloud.

4️⃣ Multi-Cloud / Cross-Cloud

Now there is another concept that initially sounded very similar to hybrid cloud.

It's Multi-Cloud.

What is Multi-Cloud?

Multi-cloud means using two or more different public cloud providers.

For example:

AWS + Azure + Google Cloud

A company doesn't necessarily have to use only one cloud provider.

It can use different providers for different requirements.

🤔 Why would a company use multiple cloud providers?

There are a few reasons.

1. Avoid vendor lock-in

If a company uses only one cloud provider for everything, it may become heavily dependent on that provider.

Using multiple providers can reduce this dependence.

2. Use the best tool for each job

Different cloud providers offer different services and capabilities.

A company might decide:

"I'll use this provider for one workload and another provider for a different workload."

The idea is to choose the tool that works best for a particular requirement.

3. Cost

Companies can also compare different providers and choose an appropriate option for different workloads.

So multi-cloud can sometimes help with cost optimization.

The notes describe these three ideas as avoiding lock-in, using the best tools, and choosing cost-effective options.

⚠️ Hybrid Cloud vs Multi-Cloud

This is probably the most important difference to remember from today's topic.

I used to think these two were basically the same, but they are not.

Hybrid Cloud

Uses:

Private Cloud + Public Cloud

Example:

Private Cloud + AWS

Multi-Cloud

Uses:

Multiple Public Cloud Providers

Example:

AWS + Azure + Google Cloud

**So the easiest way I remember it is:

🔄 Hybrid = Private + Public

🌍 Multi-Cloud = Public + Public + Public

📊 Quick Comparison**

Here's the comparison I made while learning this topic:

The important thing isn't to memorize this table word by word.

Try to understand the basic difference.

🧠 A Simple Way to Remember All Four

If you are preparing for an exam, interview, or just trying to understand the concept, remember these four lines:

☁️ Public Cloud

Someone else owns the infrastructure and I use it.

🔐 Private Cloud

My organization has a dedicated cloud environment and more control over it.

🔄 Hybrid Cloud

I use both private and public cloud environments.

🌍 Multi-Cloud

I use multiple public cloud providers.

That's honestly enough to build a strong basic understanding.

🤔 Which One Should a Company Choose?

There isn't one deployment model that is perfect for everyone.

It depends on the company's requirements.

For example:

A startup

May prefer Public Cloud because it can start using infrastructure without purchasing physical servers.

An organization needing a dedicated environment

May consider a Private Cloud because it provides greater control.

A company with sensitive data + changing workloads

May choose Hybrid Cloud so it can keep certain workloads private while using public-cloud resources when required.

A company wanting to use different cloud providers

May choose a Multi-Cloud strategy to reduce vendor dependence or use different providers for different workloads.

🔥 The One Thing I Learned Today

The biggest thing I understood from this topic is that cloud doesn't always mean the same thing.

When someone says:

"Our company uses cloud."

That doesn't immediately tell us:

Where the infrastructure is located
Who owns it
Who manages it
Whether they use one provider or multiple providers

That's exactly why deployment models are important.

They help us understand how the cloud environment is actually set up.

🎯 Final Summary

My simple way of remembering today's topic is:

PUBLIC
↓
Cloud provider's infrastructure

PRIVATE
↓
Dedicated to one organization

HYBRID
↓
Private + Public

MULTI-CLOUD
↓
Multiple Public Cloud Providers

If you're also learning cloud computing, don't try to memorize complicated definitions at first.

Just ask yourself three questions:

Where is the infrastructure?

Who manages it?

How many environments/providers are being used?

Once you answer those three questions, these deployment models become much easier to understand.

🚀 Day 2 Complete!

This was Day 2 of my cloud computing learning journey.

I'm trying to learn these concepts step by step and, at the same time, explain them in a way that another beginner can understand without getting overwhelmed by complicated terminology.

If you're also learning cloud computing, which deployment model makes the most sense to you — Public, Private, Hybrid, or Multi-Cloud?

Let me know in the comments! 👇

See you in Day 3! ☁️