Hybrid cloud is an IT architecture that incorporates some degree of workload portability, orchestration, and management across 2 or more environments. Depending on whom you ask, those environments may need to include:
- At least 1 private cloud and at least 1 public cloud
- 2 or more private clouds
- 2 or more public clouds
- A bare-metal or virtual environment connected to at least 1 cloud—public or private
These varying requirements are an evolution from the earlier age of cloud computing, where the differences between public clouds and private clouds were easily defined by location and ownership. But today’s cloud types are far more complex, because location and ownership are abstract considerations. For example:
Private clouds traditionally ran on-premises, but organizations are now building private clouds on rented, vendor-owned data centers located off-premises.
This is why it can be more helpful to define hybrid cloud computing by what it does. All hybrid clouds should:
- Connect multiple computers through a network.
- Consolidate IT resources.
- Scale out and quickly provision new resources.
- Be able to move workloads between environments.
- Incorporate a single, unified management tool.
- Orchestrate processes with the help of automation.
The way public clouds and private clouds work as part of a hybrid cloud are no different than how standalone public clouds or private clouds work:
- A local area network (LAN), wide area network (WAN), virtual private network (VPN), and/or application programming interfaces (APIs) connect multiple computers together.
- Virtualization, containers, or software-defined storage abstract resources, which can be pooled into data lakes.
- Management software allocates those resources into environments where applications can run, which are then provisioned on-demand with help from an authentication service.
Separate clouds become hybrid when those environments are connected as seamlessly as possible. That interconnectivity is the only way hybrid clouds work—and it’s why hybrid clouds are the foundation of edge computing. That interconnectivity is how workloads are moved, management is unified, and processes are orchestrated. How well-developed those connections are has a direct impact on how well your hybrid cloud works.
Every cloud is unique. Private clouds are one-of-a-kind and there are thousands of public cloud providers. There's no one-size-fits-all cloud architecture. The way you organize your cloud resources and build a hybrid cloud will be as unique as your fingerprint. But there are a few basic principles that correspond to 2 general ways of building a hybrid cloud environment: The traditional way and the modern way.
Traditional hybrid cloud architecture
Hybrid clouds used to be the result of literally connecting a private cloud envrionment to a public cloud environment using massive, complex iterations of middleware. You could build that private cloud on your own, or you could use prepackaged cloud infrastructure like OpenStack®. You would also need a public cloud, like one of the few listed below:
Finally, you would need to link the public cloud to the private cloud. Moving huge amounts of resources among these environments require powerful middleware, or a preconfigured VPN that many cloud service providers give customers as part of their subscription packages:
- Google Cloud offers Dedicated Interconnect.
- Amazon Web Services (AWS) offers Direct Connect.
- Microsoft Azure offers ExpressRoute.
- OpenStack provides the OpenStack Public Cloud Passport.
Modern hybrid cloud architecture
Today’s hybrid clouds are architected differently. Instead of connecting the environments themselves, modern IT teams build hybrid clouds by focusing on the portability of the apps that run in the environments.
Think about it like this: Instead of building a local 2-lane road (fixed middleware instances) to connect 2 interstate highways (a public cloud and a private cloud), you could instead focus on creating an all-purpose vehicle that can drive, fly, and float. Either strategy still gets you from one place to another, but there's a lot less permitting, construction, permanancy, and ecological impact if you focus on a universally capable vehicle.
Modern IT teams build hybrid clouds by focusing on the car—the app. They develop and deploy apps as collections of small, independent, and loosely coupled services. By running the same operating system in every IT environment and managing everything through a unified platform, the app's universality is extended to the environments below it. In more practical terms, a hybrid cloud can be the result of:
- Running Linux® everywhere
- Building and deploying cloud-native apps
- Managing everything using an orchestration engine like Kubernetes or Red Hat OpenShift®
Using the same operating system abstracts all the hardware requirements, while the orchestration platform abstracts all the app requirements. This creates an interconnected, consistent computing environment where apps can be moved from one environment to another without maintaining a complex map of APIs that breaks every time apps are updated or you change cloud providers.
This interconnectivity allows development and operations teams to work together in a DevOps model: A process by which teams work collaboratively across integrated environments using a microservice architecture supported by containers.
Because you can use the best of every cloud. Command Line Heroes host Saron Yitbarek investigates how open source can connect multiple environments into a hybrid cloud.
A properly designed, integrated, and managed hybrid cloud can be as secure as traditional on-premise IT infrastructure. While there are some unique hybrid cloud security challenges (like data migration, increased complexity, and a larger attack surface), the presence of multiple environments can be one of the strongest defenses against security risks. All those interconnected environments let enterprises choose where to place sensitive data based on requirements, and it lets security teams standardize redundant cloud storage that can augment disaster recovery efforts.
Because it’s hard to get the benefits of a unified environment when proprietary code stands in the way. That’s why we promote an open hybrid cloud strategy as a way enterprises can achieve their digital transformation objectives.
An open hybrid cloud strategy brings the interoperability, workload portability, and flexibility of open source software to enterprise environments. Everything above and below the operating system is abstracted—every environment, every app—thereby providing consistent interaction with any app in nearly any environment without retooling the app, retraining people, splitting management, or sacrificing security. And because it's all open source, your data will move with you—no matter where tomorrow takes you.