Cloud Computing

What is Public Cloud? Definition, How It Works and More


Cloud computing concept.
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The stats for public clouds depict a healthy state of affairs. According to Statista, revenue in the public cloud market is projected to reach $525.6 billion in 2023. Furthermore, the market’s largest segment is software as a service, which has a projected market volume of $253.9 billion this year.

SEE: Forrester predicts the public cloud market to reach $1 trillion by 2026.

With this in mind, it’s worth understanding what the public cloud is and how it works as well as considering its key benefits, drawbacks and features.

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What is a public cloud?

A public cloud is a type of cloud computing where a third-party service provider offers computing resources, including software applications, virtual machines and complete infrastructures, over the public internet. These resources are shared among multiple users but are kept secure and segregated to ensure privacy and security.

There are three types of public clouds:

  • Infrastructure as a service: Where the cloud provider furnishes all computing infrastructure components such as servers, storage and virtualized systems.
  • Platform as a service: Where the cloud provider furnishes hardware and software tools that clients use to develop their own applications.
  • Software as a service: Where the cloud provider hosts applications, it’s expert in and delivers the applications to clients.

Among popular public cloud service providers are Amazon Web Services, IBM, Google, Microsoft, Oracle and Salesforce.

Key features of public clouds

  • Multitenancy: Public clouds operate on a multitenant architecture, meaning computing resources are shared among multiple users, who operate in separate and secure partitions within the cloud.
  • Resource pooling: Public cloud architecture is designed to pool resources such as processing power, network bandwidth and storage. This pooled model increases efficiency and allows for dynamic distribution of resources as per user demand.
  • Broad network access: These clouds are typically accessible over the internet, allowing users to access services and manage resources from anywhere using a variety of devices like laptops, smartphones and tablets.
  • On-demand self-service: Public cloud users can provision computing resources as needed, excluding human involvement with the service provider. This on-demand model provides flexibility and speed in deploying applications.
  • Elasticity and scalability: Public cloud architecture is designed to be highly elastic and scalable. Users can quickly scale up resources to handle peak loads and scale down when demand decreases, often automatically.
  • Metered billing: In public cloud architecture, users are billed based on their usage of resources. This pay-as-you-go model eliminates the need for significant upfront capital expenditure on IT infrastructure.

How does the public cloud work?

Public cloud operates on a shared infrastructure model, where multiple users access the same physical resources such as servers, storage and network devices. These resources are owned and managed by a third-party cloud service provider and are divided into multiple virtual instances through virtualization. Each user accesses their own virtual environment, which appears as a separate, private network, despite the shared underlying hardware.

SEE: Take advantage of TechRepublic Premium’s cloud engineer hiring kit to find the right fit for your team.

The allocation of resources in the public cloud is managed by the cloud service provider’s management software, often referred to as the cloud orchestration platform. This platform enables the automatic allocation of virtual resources based on user requests, ranging from a single virtual machine to a complex multi-tier application environment. The public cloud also employs automation for resource provisioning, scaling and management, allowing users to quickly adjust resources based on their needs.

Public clouds use distributed storage systems for data management, spreading data across multiple physical disks in different locations for high availability, redundancy and fast data access. Security measures, including encryption, identity and access management, and physical security controls, are implemented to protect the shared infrastructure and users’ data. Thus, the public cloud leverages virtualization, automation and distributed storage technologies to provide scalable, on-demand computing resources over the internet.

Benefits of public clouds

Frees IT staff

Third-party cloud service providers manage public clouds, so IT departments don’t have to worry about managing applications infrastructure or networks at all. This allows IT staff to focus on other work.

Dedicated experts

In some cases, especially for smaller companies, on-staff expertise may be lacking for IT platforms and services. Public cloud services providers typically have on-staff expertise that can handle computing tasks and fill in any IT skills gaps.

Shared cost

Since a public cloud services provider supplies computing resources for many different companies, the costs of the cloud are shared. This can lower overall enterprise IT costs, especially for businesses with fluctuating needs.

Flexible infrastructure

Public cloud infrastructures are flexible. If more computing power or storage is needed, businesses can scale their needs upwards on the spot. Conversely, businesses can also downscale resources when they’re no longer needed.

Compared to an amortized capital investment in software or hardware for data centers, where businesses continue to pay even when resources are dormant, public clouds tend to be more flexible and affordable.

Drawbacks of public clouds

Shared resources

One of the main drawbacks of public clouds is sharing computing resources with others. Even though public cloud providers ensure client computing is kept secure and segregated, being in a shared environment may not be secure enough for some clients, especially those dealing with sensitive data.

SEE: Consider using a private cloud.

Potential for slower data transmission

For clients that require exceptional transaction processing speeds, the public cloud may not be the best choice. Since public clouds are commonly accessed over the public internet, data transmission rates may be slower compared to private networks. This could impact real-time or latency-sensitive applications.

Limited control and customization

In a public cloud, the cloud service provider controls and manages the underlying infrastructure. As a result, customers have limited control over the hardware and software and may not be able to customize the environment to the same extent as they could with a private cloud or on-premises infrastructure.

Compliance and regulatory concerns

For organizations operating in heavily regulated industries such as healthcare or finance, compliance can be a challenge. Data residency and privacy laws may restrict where data can be stored and processed, which can be difficult to manage in a public cloud environment.

Public cloud pricing

The cost of public cloud services can vary widely depending on the specific services used, the amount of resources consumed and the pricing model of the cloud provider. It’s challenging to provide an average cost due to these variables, so pay-as-you-go models are more common.

These models ensure businesses only pay for the resources they use, so public cloud can be more cost-effective. However, costs can quickly add up with heavy usage.

SEE: Consider a hybrid cloud approach.

Public cloud security

In the public cloud, the cloud provider and the customer share responsibility for security. The cloud provider secures the underlying infrastructure, including the physical data centers, servers and networking hardware. They typically offer a range of security features, including encryption, firewalls and access controls.

However, customers are responsible for securing their data and applications within the cloud, including managing user access, protecting data privacy and complying with relevant regulations.

Public cloud providers

Some of the top public cloud providers include Amazon Web Services, Microsoft Azure and Google Cloud.

Amazon Web Services

AWS is one of the leading public cloud providers. They offer an array of global cloud-based services spanning compute, analytics, networking, management tools, IoT, mobile, storage, databases, developer tools, security and enterprise applications. AWS is known for its scalability, security and extensive suite of cloud services.

Microsoft Azure

Microsoft Azure is another major player in the public cloud market. Azure provides a huge variety of cloud services covering computing, storage, networking and analytics. Azure is well-integrated with other Microsoft products, making it a popular choice for organizations that use a lot of Microsoft software.

Google Cloud Platform

GCP offers cloud computing services that run on the same infrastructure that Google uses internally for its consumer-facing products such as YouTube and Google Search. GCP provides services such as computing, data storage, data analytics and machine learning. It’s popular for its strong capabilities in data analytics, AI, ML and its competitive pricing.

Should your organization use a public cloud?

Organizations considering public cloud services should initiate their decision-making process by evaluating their specific IT requirements and budget. They should consider factors such as the size of the organization and the intended use of the cloud. For instance, a smaller company might be interested in completely transferring its IT operations to the cloud, while another might only want to use the public cloud for application testing before hosting them in-house.

Certain organizations might be seeking a public cloud provider that offers specialized software and expertise in a specific domain, such as sales or finance. The needs are diverse and vary from one organization to another and for some, public cloud services might not be a suitable option. However, for many others, public cloud providers present flexible IT deployment and cost alternatives that can prevent significant internal data center expenditures.

If you’re still unsure if a public cloud infrastructure suits your business’s needs, see how it compares to hybrid and private cloud options, or consider adopting a multicloud approach.