Businesses are migrating to the cloud, but which cloud is the right type of cloud for your business? The performance and affordability of private cloud architecture are making private clouds a popular choice for business of all sizes. In the latest part of our cloud architecture series, we interviewed experts on private cloud architecture. In this post, we explore private cloud architecture with TierPoint’s James Bruce, Senior Manager of Architecture, and Steve Foster, Cloud Architect.

What is private cloud architecture?

Interviewer: In this post, we’ll explore private cloud architecture. To start, what is private cloud architecture?

Steve: A private cloud is customized and purpose-built to a customer’s detailed requirements, instead of being built to suit the needs of others. All the resources are dedicated to a single entity or tenant – an individual, a group within a business, or an entire company.

James: All the compute, all the storage, and all the network are dedicated to that one entity without sharing resources with others. Refrigerator-sized racks of high-capacity x86 servers with multi-core processors and enormous amounts of memory form the compute. Data for the business lives in the storage. Storage performance has increased considerably over the past 10 years, and faster access times open avenues for data exploration. Then, the network. A private cloud requires a good, resilient network to utilize the high-performance compute and storage. The network facilitates the transfer of data from storage to compute and back, from server to server, and from user to server.

The software in a private cloud is directed by a type of operating system called a hypervisor. A workload or application typically runs on an operating system – applications can’t access hardware directly. On behalf of the applications, the OS interfaces with the hardware components – the CPU, the memory, the storage, and the network. The hypervisor enables the creation of multiple virtual machines – each running its own OS – on a single physical device. The hypervisor serves as a master gatekeeper over a single pool of compute, storage and network resources for the virtual machines to share. A private cloud architecture is like a cake: the bottom layer is the hardware, the middle layer is the hypervisor, and on top are cupcakes – each a virtual machine.

Steve: Through the VMs the hypervisor abstracts the hardware resources and manages access to them – taking time sharing and time slicing to the next level by fully virtualizing the whole stack, including storage and network. The hypervisor enables software-defined storage, software-defined networking and security features. Automation and orchestration of deployments and life cycle management, such as firmware upgrades, are also integrated into and managed by the hypervisor.

Benefits of private cloud architecture

Interviewer: I’m imagining that cupcake confection now. Let’s explore further. Why would a business set up a private cloud architecture?

James: The first of several reasons a business would opt for a private cloud is performance. In other types of clouds, your workload shares physical resources with others. Like an airline that expects some passengers not to show, a public cloud may allow more VMs to be provisioned than it can run at full capacity. This allows the cloud to extract the most value from the physical hardware, and it works because most of the time, applications sit idle. Unfortunately, sometimes all the ticket holders show up for a flight. Over-subscription has side effects when others consume all the resources. A hypervisor does its best to balance the load, but sometimes there are not enough resources available to accommodate all of the requests, so performance suffers. When you own a private cloud, you own the hardware and control the level of oversubscription to suit the needs of your business and the characteristics of your applications. No other entity can consume the resources.

Steve: A close second would be availability. You have control to ensure the availability required by your business – if you need a very high level of resiliency and redundancy, you can get it with a private cloud. The customer can select from multiple availability options, such as node failover and more granular availability options. They could decide on a chassis that contains multiple servers for redundancy or rack-level availability enhancement to survive a full-rack outage. You have control over availability in other ways too, such as deciding when upgrades take place and how change management is handled.

James: Some of the other benefits of private clouds are security, compliance and geographic specificity. Simply not sharing physical hardware or software makes it easier to create a better security posture and to meet compliance mandates. A private cloud also enables geographic choice and can improve availability locally. Public clouds tend to congregate in a limited number of areas with greater internet bandwidth, such as Texas, Washington State, and New York City. You can put a private cloud anywhere it benefits the business.

Steve: Lastly, a deciding factor in favor of a private cloud may be familiarity, comfort and the availability of expert and managed hosting services. A private cloud architecture can enable a customer to fully leverage the expertise of the IT staff they already have. As the closest cloud technology to what many companies are doing in house, a private cloud can be an excellent choice for businesses stepping into cloud computing. Your staff know the hardware and how it works at a deep level because you decide what’s in your private cloud architecture. Also, when you want help, a private cloud hosting provider, such as TierPoint, can guide you in selecting the best vendors and services to meet your specific requirements.

Also read: Big Benefits of Private Cloud (and How to Take it to The Next Level)

Private cloud vs. public cloud architecture

Interviewer: How does a private cloud architecture differ from a public cloud architecture?

James: Fundamentally, the compute, storage, and network components are the same in private clouds and public clouds. The biggest difference is scale, and that difference in scale is huge. A private cloud is much smaller than a public cloud. Another difference is software architecture, which results in different interfaces for consuming resources. A private cloud can run more applications without rewriting or refactoring them and can ease compliance with legacy software licensing terms that weren’t written with cloud computing in mind.

Steve: Isolation from other customer workloads is another difference. Isolation can be important for security – and for compliance where a customer can't allow their data to coexist in a public cloud that is also storing the data of other customers. Isolation also improves performance in that it prevents noisy neighbor situations. A customer may want to be able to guarantee that the performance they require is always available to their workloads, and they can’t do that if they share resources with other customers.

Cost of ownership: Private vs. public cloud architecture

Interviewer: Before we go, is there anything more you would like to add?

James: Costs are often a deciding factor in business decisions. You control costs and eliminate surprise bills with a private cloud. Unforeseen costs are common with a public cloud, especially when a business first migrates. On the other hand, private cloud architecture has a minimum footprint, which may drive costs too high for a very small business. In that case, costs would be lower in a public cloud, but fewer businesses are starting to fit that model. Hardware for private clouds continues to drop in price and, paired with hyperconverged infrastructure, a private cloud architecture can be practical for even a small office with a few employees. The low barrier to entry of a private cloud can sum to less than the price of a new car. In these ways, a private cloud can help a business of any size ensure predictable and controlled cloud computing costs.

More on cloud architecture

Stay tuned for the next part where we discuss how private cloud and hyperconverged infrastructure work together. To learn more about managed private cloud for your business, contact us today. 

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