There's more to private clouds than control over infrastructure and security. Consider the benefits of private cloud services before jumping on the public cloud bandwagon.
Many organizations are running mission-critical workloads in public or hybrid cloud environments. But there are also several advantages to using a private cloud.
Private cloud services offer similar capabilities to those that major public cloud providers can deliver except they do so by using organization-owned resources that reside on premises. One of the most appealing private cloud advantages is that organizations can use their existing hardware and software resources. This enables users to keep their hardware on premises, select the exact hardware they want to support their private cloud and have greater control over security. Other advantages include potential cost savings, scalability and stronger compliance features.
Control over hardware choices
Public cloud providers keep their prices low by sharing hardware among multiple tenants. Although larger public cloud providers allow tenants to lease dedicated hardware, this hardware comes at a price that is substantially higher than shared offerings. There is also the potential for noisy neighbor syndrome.
Because an organization's hardware supports its private cloud, it has the freedom to select the hardware it uses and the resources that best meet its needs. A business can decide whether to use cutting-edge hardware or make use of lower-end commodity options. With full access to this hardware, users can perform upgrades or maintenance on an as-needed basis.
Additionally, dedicated hardware eliminates the security risks associated with sharing hardware with tenants outside the organization. With hardware resources on premises, organizations can mandate their security.
Because an organization's hardware supports its private cloud, it has the freedom to select the hardware it uses.
The issue of scalability
When it comes to scalability, public clouds have a distinct advantage. Public cloud providers have servers in their data centers providing extra capacity any time it's needed. They also make it easy to scale workloads up or down in response to demand spikes.
It is possible to build a private cloud that allows workloads to scale as needed. However, there is one critical difference between public and private clouds in this regard. Public clouds offer near-limitless scalability. Scalability in private clouds is limited by an organization's hardware resources. Workloads can be scaled up to the point that they exhaust all the unused capacity within the private cloud but cannot scale beyond that point.
Though users might need to add new resources to scale private cloud environments, it's relatively common for an organization to begin by creating a small private cloud. The organization can then expand its existing hardware over time. However, that hardware comes at a cost. Furthermore, data center hardware only provides ROI when the hardware is being used. Hardware that exists solely for the purpose of providing unused capacity is not providing ROI unless a spike occurs.
Rather than investing heavily in extra private cloud capacity, most organizations embrace the hybrid approach to scale up. Those resources are then released when the workload can be scaled back down.
Explore major differences between public cloud and private cloud.
Granular control over infrastructure
Private cloud services provide complete control over the entire infrastructure. Users can base their private cloud around virtualization tools, such as Hyper-V and Microsoft System Center, or a VMware-based infrastructure. The user has full control.
However, a hypervisor such as VMware, Hyper-V or Kernel-based Virtual Machine is not the only option. Those who wish to build a private or hybrid cloud that mimics the public cloud can opt to purchase resources from public cloud providers. For example, Microsoft offers Azure Stack Hub, which lets organizations run Azure services in their own data centers. Similarly, Amazon offers AWS Outposts, which consists of a fully managed AWS infrastructure that runs on premises.
The main advantage to building a private cloud -- as opposed to using public cloud alternative services -- is control. Having control of a private cloud gives access to resources that aren't exposed by public cloud providers. Some public cloud providers offer cloud-based directory services, but they block access to some of the group policy settings and built-in accounts. These providers also usually prevent access to low-level hypervisor settings to prevent any intervention with the provider's security model and their ability to manage the cloud infrastructure.
Sizing instances to match exact requirements
A private cloud environment gives users the ability to establish granular control of the sizing of VM instances. When creating a new VM instance in AWS, for example, you have to choose from several predetermined instance sizes. The instance size determines the amount of memory, CPU and storage resources that are available to the VM instance.
However, the predefined instance sizes might not meet an organization's exact requirements. Users might have to settle for an instance that's smaller than they prefer, which can affect performance. Conversely, users might have to select an instance that is larger than needed, which increases costs and wastes resources. A private cloud provides flexibility to size instances to match exact requirements.
Avoiding monthly bills and fluctuating costs
One of the main reasons the public cloud became popular was the promise of cost savings. The public cloud offered consumption-based pricing, which freed organizations from having to make large upfront investments in server hardware and software.
In retrospect, this consumption-based pricing model has been beneficial for startups and for small businesses who lack the ability to purchase data center hardware. The public cloud can also save money when it comes to running new workloads without the necessary hardware and software.
When it comes to existing workloads, however, many organizations aren't seeing these promised cloud savings. In some cases, organizations are even finding that it costs more to run a workload in the public cloud than it does to run it in-house. As such, the last few years have seen organizations repatriating cloud-based workloads by bringing those workloads back into their own data centers.
One of the greatest benefits of using a private cloud was avoiding monthly bills from a cloud provider. However, some of the major data center hardware vendors have begun to implement their own consumption-based pricing. In other words, hardware usage is metered, and the organization must pay a monthly fee based on its hardware use. Businesses must ensure that they are aware of any ongoing financial commitments associated with hardware purchases.
There are other advantages to using nonmetered hardware besides not receiving a bill each month. Organizations can avoid cost fluctuations that are so common with the public cloud. In the public cloud, costs tend to increase over time as data accumulates and users deploy more demanding workloads. These instances, in conjunction with cloud providers' complex billing calculations, can make cloud costs difficult to predict.
Finally, there have been several instances over the past several years of public cloud providers experiencing outages. Private clouds aren't immune to outages. However, using a private cloud does ensure that users have the control to manage these outages without having to wait for their cloud provider to solve the issue. Avoiding further downtime can help organizations save money.
The different models of private cloud provide users with varying amounts of convenience and control.
Staying compliant
Private clouds were once the obvious choice for organizations who were subject to regulatory compliance mandates. Private clouds allow an organization to have complete and total control over the low-level cloud infrastructure, which can be helpful with compliance. More importantly, private clouds guarantee data sovereignty and make it easy to guarantee that data is being stored domestically.
However, today, it is no longer so cut and dry. Public cloud has had time to mature, and service providers know that nearly all their biggest customers are subject to regulatory requirements. As such, public cloud providers go to great lengths to ensure that their services are compliant with various regulations. AWS, Microsoft and Google have industry cloud offerings that provide specialized services and capabilities to serve security- and compliance-focused industries, such as finance and healthcare companies.
Both public and private clouds can be made compliant. In some cases, it might be easier to ensure compliance within the public cloud. This is because public cloud providers have already done so much of the work. This is particularly true for organizations that opt to run a workload using a managed service within the public cloud, as opposed to building a solution using cloud-based VM instances.
Brien Posey is a former 22-time Microsoft MVP and a commercial astronaut candidate. In his more than 30 years in IT, he has served as a lead network engineer for the U.S. Department of Defense and a network administrator for some of the largest insurance companies in America.
