Public Cloud vs Private Cloud: A Comprehensive Guide for IT Leaders

Both public and private cloud environments allow an organization to access IT resources, such as data storage and processing power on an as-needed basis. However, public clouds are hosted by a third-party provider, while private clouds are managed in-house within an organization’s own data center.

As cloud computing grows in popularity, IT leaders need to understand the benefits and disadvantages of each to make the best choice for their organizations. Cloud deployments should be tailored to the use case and the needs of the business as a whole. 

In-Depth Technical Comparison of Public and Private Clouds

Networking Architecture

Public and private cloud environments have very different architectures. This is true both at the endpoint and network level.

Public clouds are multi-tenant systems where different users share the same physical hardware. Isolation between different user environments is implemented at the software layer using virtualization technology. Private clouds are hosted within an organization’s own data center and on its own hardware. This means that the company has full control over its infrastructure and doesn’t share the environment or resources with other users.

Security Models

Another substantial difference between public and private cloud environments is in their security models. Public clouds operate under the shared responsibility model, where security responsibilities are divided between the cloud provider and their customers. Public cloud users are responsible for reviewing the security requirements for the services that they are using and implementing the appropriate security controls and configuration settings.

In a private cloud ecosystem, the organization has the dual role of cloud provider and cloud customer. This means that the company has full control over its own security. This is both an advantage and a downside since it provides the organization with increased control at the cost of additional security responsibility. 

Strategic Guidance for Hybrid and Multi-Cloud Approaches

Hybrid cloud and multi-cloud environments split an organization’s cloud ecosystem across multiple different platforms. This could be a public and private cloud or multiple public clouds. When allocating workloads and resources, it’s important to weigh the pros and cons of each environment.

Workload Placement Criteria

In a hybrid or multi-cloud environment, an organization can choose to deploy its workloads in various locations. Some key considerations when deciding where to place a workload include:

• Performance Requirements: Often, public cloud offer greater scalability and flexibility than private clouds due to the provider’s more extensive and optimized infrastructure. Workloads with high performance requirements may be better deployed in public clouds, and some clouds may offer additional optimizations and advantages over others in a multi-cloud environment.
• Data Sensitivity: Applications may have access to and process sensitive data that needs to be secured in accordance with corporate and regulatory security requirements. Private cloud environments provide an organization with greater control over its infrastructure and environment, offering lower security risk than multi-tenant public cloud environments.
• Regulatory Constraints: Organizations may also need to consider regulatory constraints and requirements when selecting where to host a workload. For example, data localization requirements may mandate that certain data be hosted within a country where a private cloud is the only viable option.

Optimizing Resource Allocation

Efficient resource allocation is a common challenge that organizations face in cloud environments. Some ways to reduce the cost of cloud computing include:

• Balancing Cost and Performance: In cloud environments, companies can pay for improved performance, access to resources, etc. When planning a cloud deployment, weighing the pros and cons of higher and lower-tier cloud services can help to optimize resource allocation.
• Leveraging Cloud-Native Services: Cloud-native services are designed to take full advantage of cloud environments, allowing them to scale on demand by allocating or deallocating resources as needed. Using cloud-native services enables an organization to only pay for the resources it needs and uses rather than purchasing unneeded capacity just in case it’s needed.

Emerging Trends Impacting Public vs Private Cloud Decisions

Edge Computing

Edge computing moves data processing to the network edge, deploying additional computational power on Internet of Things (IoT) devices or gateways geographically close to them. By performing some level of preprocessing before sending data to the cloud, edge computing reduces network latency and bandwidth requirements between IoT devices and cloud environments.

Edge computing can have various impacts on cloud computing. One potential impact is a decrease in public cloud utilization since a greater percentage of data processing is moved to edge systems. Another potential result is that organizations deploy additional private cloud capabilities to perform processing closer to IoT devices.

AI and Machine Learning

The rise of artificial intelligence and machine learning (AI/ML) has significant implications for cloud computing. AI models require large volumes of data and significant computational power to train and operate.

Cloud environments are a logical location to train and deploy AI services due to their scalability and flexibility. Many public cloud providers have begun offering services to help organizations build and deploy their own AI-based solutions. However, organizations may also want to keep their AI models in-house for privacy and security reasons. If this is the case, an organization may need to invest significantly in private cloud infrastructure to ensure that it has adequate data storage and computational capacity to effectively train and operate these systems.

Serverless Computing

Serverless computing abstracts away the underlying infrastructure that an application relies upon. When configuring and deploying an application, the cloud provider is responsible for ensuring that it has access to the storage, compute, etc. that it needs.

Serverless computing offers companies the ability to take full advantage of the capabilities of cloud computing. Unlike traditional applications that were “lifted and shifted” to the cloud, serverless applications can allocate and deallocate resources at need, ensuring that they only use what is required for the task at hand.

Compliance and Data Sovereignty in the Cloud

Meeting Regulatory Requirements

Many data protection laws have requirements on how sensitive data must be protected. This might involve implementing certain security controls or limiting access to sensitive data on a need-to-know basis.

Regulatory compliance can be more difficult in public cloud environments where an organization lacks full control over its underlying infrastructure. This deployment environment may make it infeasible to use certain security solutions, and achieving compliance may require configuring various vendor-provided configuration settings and security controls.

In contrast, private cloud environments are completely under the control of the organization. While they lack the same advantages as the public cloud, they can simplify data security and regulatory compliance efforts.

Country-Specific Considerations

Beyond data security challenges, public clouds also introduce considerations regarding country-specific laws and data localization requirements. If an organization’s cloud provider is located in a particular country, then that country’s laws may apply to the organization’s data.

From the other side, laws like the GDPR impose restrictions on cross-border data transfers of EU citizen data. While many public cloud providers have means of complying with these requirements, the fact that an organization never truly knows where its data is stored, backed up, etc. in the cloud means that it can’t be absolutely certain that it is compliant with these regulatory requirements.

Making the Right Choice for Your Organization

On the one hand, public cloud infrastructure enhances infrastructure flexibility and scalability, and can be a more cost-effective option for the business. On the other, private cloud environments provide the organization with more control over their cloud environments, which is beneficial for regulatory compliance.

When developing a cloud strategy, it’s essential that an organization’s decisions align with the organization’s business goals. In most cases, a hybrid or multi-cloud environment is the best choice for the business as it provides the opportunity to take advantage of the benefits of both options on a case-by-case basis. When developing your cloud strategy, carefully consider your cloud needs and develop a strategy tailored to your business and use cases.