Hybrid cloud infrastructure varies according to an organization's specific business objectives, yet all still share a mix of computing environments, including the following.

On-premises ("on-prem")

On-premises is a traditional computing environment where an organization runs and manages its own hardware, software, data storage and other computing resources at its own physical location. Examples include an office building or an on-premises data center.

Private cloud

Private cloud is a cloud computing environment where all resources are isolated and operated exclusively for one customer. Private cloud combines many benefits of cloud computing with the security and control of on-premises IT infrastructure.

Organizations in industries that deal with strict regulatory compliance and sensitive (for example, banking, healthcare and government) usually require private cloud settings.

Public cloud

Public cloud is a cloud computing setting hosted by a third-party cloud service provider (CSP), such as Amazon Web Services (AWS), Microsoft Azure, IBM Cloud® or Google Cloud.

These CSPs host public cloud IT resources like virtual machines (VMs) to complete enterprise-grade infrastructures and development platforms over the public internet on a “pay-as-you-go” pricing basis.

These are four main public cloud service offerings that provide different levels of support and service:

1. Software-as-a-Service (SaaS) is on-demand access to ready-to-use, cloud-hosted application software.
2. Platform-as-a-Service (PaaS) is a complete cloud platform—hardware, software and infrastructure—for developing, running and managing applications.  
3. Infrastructure-as-a-Service (IaaS) is a cloud computing model that delivers fundamental compute, network and storage resources.
4. Serverless computing (serverless) is an application and execution model that allows developers to build and run application code without provisioning or managing servers or back-end infrastructure.

For a deeper dive on how these different public cloud service offerings compare, see “What are IaaS, PaaS and SaaS?”

Besides a mix of on-prem, private cloud and public cloud settings, hybrid cloud architecture relies on the following critical components:

• Network connectivity
• Virtualization
• Containerization
• Hybrid cloud management platform

Network connectivity

Hybrid cloud deployments require robust networking capabilities, including wide area network (WAN), virtual private network (VPN) and application programming interfaces (APIs).

Virtualization

Hybrid cloud architecture relies on virtualization technology, enabling the division of a single computer's hardware components—such as processors, memory and storage—into multiple virtual machines. Virtualization enables better resource utilization and flexibility by allowing users to run multiple applications and operating systems on the same physical hardware.

Containerization

Containerization is the packaging of software code with just the operating system (OS) libraries and dependencies required to run the code to create a single lightweight executable—called a container—that runs consistently on any infrastructure.

Hybrid cloud management platform

Modern hybrid cloud computing involves a unified platform for discovering, operating and managing on-premises, private and public cloud data and resources.

Check out this video, "Hybrid Cloud Explained," which reveals how organizations can tailor a hybrid cloud environment to meet their business needs.

Traditional hybrid cloud architecture

Initially, hybrid cloud architecture focused on the mechanics of transforming portions of a company's on-premises data center into private cloud infrastructure. It also focused on connecting that infrastructure to public cloud environments hosted off-premises by a public cloud provider. Businesses accomplished this using a prepackaged hybrid cloud solution, such as Red Hat® Open Stack.  

Other methods included using sophisticated enterprise middleware to integrate cloud resources across the environments and unified management tools to monitor, allocate and manage those resources from a central console or 'single pane of glass.'

Modern hybrid cloud architecture

Today, hybrid cloud architecture focuses less on physical connectivity and more on supporting the portability of workloads across all cloud environments. It also focuses on automating the deployment of those workloads to the best cloud environment for a given business need. Several trends have driven this shift.

First off, organizations are building new applications and modernizing legacy applications to use cloud-native technologies. These technologies enable consistent and reliable development, deployment, management and performance across cloud environments and across cloud vendors.

Specifically, they're building or transforming applications to use microservices architecture, which breaks applications into smaller, loosely coupled, reusable components focused on specific business functions. And they're deploying these applications in containers, which have become the de facto compute units of modern cloud-native applications

At a higher level, public and private clouds are no longer physical 'locations' to connect. For example, many cloud vendors now offer public cloud services that run in their customer's on-premises data centers. Private clouds, once run exclusively on-premises, are now often hosted in off-premises data centers on virtual private networks (VPNs) or virtual private clouds (VPCs). Private clouds are also hosted on dedicated infrastructure rented from third-party providers.

What's more, infrastructure virtualization—called Infrastructure as Code—lets developers create these environments on demand by using any compute resources or cloud resources located behind or beyond the firewall. This technology has taken on greater significance since the explosive growth of edge computing, which improves global application performance by moving workloads and data closer to IoT devices or local edge servers.

Hybrid multicloud

Today, most enterprise businesses rely on a hybrid multicloud environment. Multicloud is a cloud computing solution that combines public cloud services from more than one cloud vendor and is portable across multiple cloud providers' cloud infrastructures. A hybrid multicloud approach creates greater flexibility and reduces an organization's dependency on one vendor, preventing vendor lock-in.

A unified hybrid multicloud ecosystem includes the following:

• Support for cloud-native application development and deployment across all cloud types (public and private) and cloud providers
• A single operating system across all environments
  
• A container orchestration platform—typically Kubernetes—that automates the deployment of applications across cloud environments

Cloud-native development lets developers transform monolithic applications into units of business-focused functionality that can run anywhere and be reused within various applications.

A standard operating system lets developers build any hardware dependency into any container. Kubernetes orchestration and automation give developers granular, set-it-and-forget-it control over container configuration and deployment (including security features for real-time monitoring, load balancing, scalability and more) across multiple cloud environments.

In a report from the IBM Institute for Business Value (IBV), the value derived from a hybrid multicloud platform technology and operating model at scale is 2.5 times the value derived from a single platform, single cloud vendor approach.

Organizations are realizing significant benefits from such a platform, including the following:

• Improved developer productivity
• Greater infrastructure efficiency
• Improved regulatory compliance and security
• Overall business acceleration

Improved developer productivity

A unified hybrid cloud platform can help expand the adoption of agile and DevOps methodologies and enable development teams to develop once and deploy to all clouds.

Greater infrastructure efficiency

With more granular control over resources, development and IT operations teams can optimize spend across public cloud services, private clouds and cloud vendors. Hybrid cloud also helps companies modernize applications faster and connect cloud services to data on cloud or on-premises infrastructure in ways that deliver new value.

Improved regulatory compliance and security

A unified platform lets an organization draw on best-of-breed cloud security and regulatory compliance technologies and implement security and compliance across all environments in a consistent way.

Overall business acceleration

This includes shorter product development cycles, accelerated innovation and time-to-market, faster response to customer feedback and more rapid delivery of applications closer to the client (for example, edge ecommerce).

Hybrid cloud offers businesses numerous use cases, including the following:

• Security and regulatory compliance
• Scalability and resilience
• Rapid adoption of new technology
• Enhancing legacy applications
• Cloud migration
• Resource optimization and cost savings
• Backup disaster and recovery (BDR)

Security and regulatory compliance

Reserve behind-the-firewall private cloud resources for sensitive data and highly regulated workloads. Use more economical public cloud resources for less sensitive workloads and data.

Scalability and resilience

Use public cloud compute and cloud storage resources to scale up quickly, automatically and inexpensively in response to unplanned spikes in traffic without impacting private cloud workloads (this is called 'cloud bursting’).

Rapid adoption of new technology

Adopt or switch to the latest AI or SaaS advancements and even integrate those solutions into existing applications without provisioning new on-premises infrastructure.

Enhancing legacy applications

Use public cloud services to improve the user experience of existing apps or to extend them to new devices.

Cloud migration

Employ cloud migration strategies, including VMware migration. 'Lift and shift' existing on-premises workloads to virtualized public cloud infrastructure to reduce the on-premises data center footprint and scale as needed without more capital equipment investment.

Resource optimization and cost savings

Run workloads with predictable capacity on private cloud and migrate more variable workloads to public cloud. Use public cloud infrastructure to quickly 'spin up' development and test resources as needed.

Backup and disaster recovery

Utilize a hybrid cloud computing model for backup and disaster recovery (BDR). BDR involves making copies of files and storing them in one or more remote locations, as well as using the copies in case of data loss or corruption.