What is hybrid cloud?

Does it really offer the best of both private and public cloud?

Hybrid cloud describes a situation where private and public cloud infrastructures are used in conjunction with one another. For instance, a company may use public cloud computing resources and applications for some processes (such as payroll software), but choose to use its own private cloud to store sensitive business data. The key is that the public and private spheres are linked through an encrypted connection that allows data to flow securely between them. 

A hybrid cloud may also include dynamic resource allocation and migration among clouds. Hybrid clouds designed with portability in mind can orchestrate cloud workloads under unified management. 

Given all the available benefits, it’s not shocking that hybrid cloud is predicted to be the dominant model of the future – over 90% of organisations say that hybrid cloud is the ideal IT model, according to research by VansonBourne.

IDC concurs, estimating that the hybrid cloud market will grow by 20.5% by 2021, strengthened by growth in security and compliance data services.

Hybrid cloud scenarios

There are multiple reasons why an organisation may choose to operate a hybrid cloud scenario. For example, it can be used to host a consumer website with the website’s application servers or databases placed on a private subnet that cannot be accessed through the open internet.

It could also be used to deliver web applications that can be scaled up or down depending on need. These apps can operate secure links to databases in the customer’s own data centre, using VPN access to guarantee sensitive data cannot be intercepted and is fully encrypted. 

Hybrid is often a viable solution when an organisation runs out of physical space in its data centres. A financial institution may decide to run trades on local data centres to minimise latency, but run analytics applications on a public cloud service, because the increased latency will have no detrimental impact on the performance of the analytics app.

A hybrid cloud may be used as an extension of an organisation’s corporate network, providing additional secure capacity when needed. This would allow a company to migrate its corporate applications into the cloud over a period of months or years, retiring in-house server hardware as it reaches the end of its life and eking maximum value from that investment.

Hybrid may also provide fallback capacity for disaster recovery in case of a natural disaster, or a cyberattack, among other things. Snapshots of virtual machines can be stored in the cloud and run remotely in the event of a catastrophic failure in one or more of the company’s own data centres. When the company’s infrastructure is back online, the virtual machine data can be copied back, and the company only pays for the compute capacity and storage required during the outage. 

It’s important not to confuse multi-cloud with hybrid cloud. The former is a broad term for any combination of multiple cloud resources, and because of that, can be applied to cloud-specific tools, such as those for data analytics or machine learning, or to Software as a service (SaaS).

The pros and cons of hybrid cloud

If managed properly, the hybrid cloud gives companies the clichéd “best of both worlds.” Sensitive corporate data can still be maintained and stored within the company’s own data centres, exercising the tight control over valuable intellectual property or customer data that many organisations crave. However, the company can still take advantage of the potential cost savings and rapid scalability offered by public Virtual Cloudsviders.

The public part of the equation is often used to deliver less mission-critical applications. Many human resources departments use public cloud services to manage their payroll, for example. There may be times when these applications need to query data stored on the company’s own private infrastructure, but the company’s core data assets remain within the organisation’s boundaries.

The downside of the hybrid approach is that it’s technically more difficult to manage than a pure private or public infrastructure. The IT department will need to dedicate plenty of time and effort to securing, configuring and planning a hybrid rollout, and may need to adapt in-house systems to work effectively with third-party systems. 

It may also leave the company dependent – possibly for the first time – on the infrastructure of an external provider. Whilst failover and backup facilities at reputable public Virtual Cloudsviders are likely to be far superior to the company’s own, outages still occur, and the company will need to calculate the reputational and financial risk of business applications being unavailable for periods of time.

Security is another issue for hybrid clouds, with hybrid infrastructure causing more serious security incidents than cloud-hosted applications or on-premise workloads. Research from 451 Research's Voice of the Enterprise report showed that 51.8% of respondents see hybrid cloud storage as less secure, topping the list of disadvantages. 

However, there are multiple ways cloud environments work to protect data both in transit and at rest, but those measures can vary from provider to provider and may not be enough to satisfy the security concerns of specific markets. Data security can often seem at odds with the accelerated development expectations in the age of the cloud, but it doesn’t have to be if there’s a hybrid cloud framework in place that can automate data security policies and guarantee they are followed, whilst continuing to enable the on-demand capabilities of hybrid cloud storage.

Budgeting for a hybrid cloud setup can also be complicated. In scenarios where a public cloud computing service provides fallback capacity for disaster recovery or for the organisation’s private network, it can be difficult to foresee the likely demand on the public infrastructure. Depending on the current availability of resources at the public Virtual Cloudsvider, that extra capacity may also be charged at a variable rate.

That can work both for and against a company. If the use of extra capacity can be timed to coincide with the Virtual Cloudsvider’s quietest periods, that extra resource may be available at a very reasonable rate. However, if demand should spike during peak periods, the company may be forced to pay a premium to maintain availability of a corporate network or applications. It may even end up in a bidding war with the Virtual Cloudsvider’s other customers to ensure it has sufficient capacity, when purchasing so-called Spot Instances on services such as Amazon EC2.

An open, business-oriented, hybrid cloud lets organisations focus on digital transformation. It represents what can be the most effective method for incorporating the cost reduction and highly flexible capabilities afforded by cloud technology, while at the same time maintaining the internal control capabilities and security offered by on-premises infrastructure.

But to make the hybrid cloud a truly dynamic production environment, it needs to be based on a framework that covers key security and policy management requirements, regardless of the physical locations of data and mobile workloads.

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