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The benefits of public cloud continue to capture the attention of enterprises, and adoption has grown significantly in the last few years. But within the public cloud megatrend, there is another deployment model that enterprises gravitate toward: virtual private clouds.
Private cloud is the go-to model for organizations that want the benefits of cloud services, but within their own facility, said Neil MacDonald, a vice president and analyst at Gartner. Virtual private clouds are a similar idea -- except, rather than enterprises owning the infrastructure, they use a private environment that's carved out of a public cloud.
"Of course, it isn't a true private cloud, but the public resources are made available only to you," MacDonald said.
While cloud giants like Amazon Web Services (AWS), Google and Azure have ridden the public cloud wave to profit and dominance, they also offer options for virtual private clouds and virtual private networks. But before deployment, it's important to understand virtual private cloud benefits and tradeoffs compared to traditional, on-premises private clouds.
Virtual private cloud benefits
Lauren Nelsonprincipal analyst, Forrester Research
Aside from their more isolated nature, one of the biggest benefits of virtual private clouds is their ability to position the public cloud as an extension of an enterprise's own data center.
"The address space can be contiguous and transactional workloads look and feel like they would in your own data center. For all intents and purposes, [a virtual private cloud] is just a workload in a remote data center," MacDonald said.
Enterprises can use their existing network and security tools to support the deployment of virtual private clouds. This means they can experience some benefits of public cloud without any radical changes.
Some other virtual private cloud benefits and use cases, according to Lauren E. Nelson, a principal analyst and private infrastructure-as-a-service cloud lead at Forrester Research are:
- Expand a disaster recovery strategy to better meet recovery time objectives and recovery point objectives;
- Meet certain compliance requirements;
- Retire older outsourced infrastructure;
- Take a more cautious approach to cloud migration, treating a virtual private cloud as a half step toward public cloud; and
- Eliminate the complexity of building an on-premises private cloud.
Virtual private clouds vs. on-premises private clouds
One of the biggest reasons organizations opt for a virtual private cloud vs. an on-premises private cloud is that building a private cloud from scratch can be tough.
"Our latest figures are that 82% of enterprises with 1,000 or more employees that try to build a private cloud fall short on areas such as self-service, automated provisioning and tracking and monitoring," Nelson said.
This is, in part, because many organizations that think they operate a private cloud really just run a standard virtualized environment.
The costs and effectiveness of an on-premises private cloud also vary. Some private cloud builders use existing tools and standard hypervisors -- basically cloud on the cheap. Others end up spending millions of dollars but do not receive much value.
"It may be basically just 20 virtual machines acting as a cloud, so it ends up being hard to justify from a [total cost of ownership] perspective," Nelson said.
Role of hybrid cloud
Other users see virtual private clouds as a way to combine cloud and on-premises computing.
Greater levels of privacy
Some users desire a more private version of virtual private clouds, Nelson said. Some vendors offer a premium version of virtual private clouds in which the physical machines are yours -- but that's typically available only for large customers. Vendors that offer this type of virtual private cloud include Rackspace, Datapipe and Internap. Telecom providers, such as Verizon or AT&T, provide a similar service to lower-tier customers, Nelson said.
"Hybrid clouds continue to grow in popularity as well as deployed usage, from storage to compute to networking," said Greg Schulz, the senior advisory analyst at StorageIO in Stillwater, Minn. "Most cloud and service providers talk about hybrid along with public clouds, while AWS tends to talk about [virtual private clouds]."
Virtual private clouds can be exclusively within AWS, or organizations can use them to connect private, on-premises resources with public clouds to support hybrid deployments. Another variation is hybrid and virtual private clouds for inter-cloud -- or connections across different providers -- as well as back to on premises, Schulz said.
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