The first public cloud service provider to achieve wide acceptance and scale was Amazon Web Services (AWS). This is an example of a true public cloud compute offering, with all the key characteristics and benefits of cloud services. Many other providers have built or are building their own public cloud offerings to provide similar capabilities. The key benefits that organizations achieve from using a public cloud are not being questioned here, but there seems to be a misconception about private cloud computing when organizations evaluate and select a provider or deployment model.
Most small and medium-sized businesses (also referred to as SMBs) do not have many choices in selecting their cloud deployment model due to their size, limited budget, internal technical expertise, and needs. Often a public cloud service offering is adequate and cost effective compared to purchasing or deploying a private cloud. For larger organizations that have size, complexity, and unique requirements, a private cloud service is often more suitable. Of course, a private cloud involves deploying the cloud services either within an on-premises datacenter, or hiring a vendor to configure a dedicated private cloud for the organization. This usually costs more money to deploy, but has significant advantages, the most important of which is the ability to customize the private cloud service to meet the organization’s security, operational, financial, and other unique requirements—something a public cloud service cannot offer and SMBs often cannot afford.
Most customers—larger organizations and government entities, in particular—desire the flexibility and scalability of public cloud offerings. Unfortunately, their unique requirements almost always force a private cloud to be considered in the end. These unique requirements, difficult to accomplish using public cloud, include customisations in the procurement, security, operational, reporting, and governance processes. Only private cloud deployments have the ability to highly customize the cloud service to meet customer requirements. Typically, the larger and more complex the customer, the larger and more complex its list of unique requirements will be. For this reason, it is important to discuss early in the planning process all requirements and their level of priority.
As new cloud customers see the potential uses and features, there is a tendency to ask for extensive customizations. Private clouds allow for more customization, but is the cost really worth it to manage one-off unique cloud platform configurations in the long run?
Table 1-1 compares private and public cloud capabilities. It does not include community, virtual private, or hybrid, because these are really just variations of private and public.
Table 1-1. Private versus public cloud characteristics
|Service catalog||Customized to customer needs||Established by provider|
|Billing and reporting||Ability to integrate with corporate billing systems||Pre-established billing and reporting; no integration with corporate billing systems|
|Service-level agreements (SLAs)||Often customized per customer requirement||Established by provider|
|Granular resource metering||Granular metering of resources||Established by provider|
|Infrastructure servers||VMs and physical servers||Normally only VMs offered|
|Security||Customized enterprise-class security||High but standardized security; rarely customizable per customer|
|Service offerings||Customized to customer needs||Established by provider|
|Self-service control panel||Customized to customer needs||Limited|
|Operations and management||Performed by provider, customer, third party, or a combination||Performed by provider|
|Security management, monitoring, and accreditation||Performed by provider, customer, third party, or a combination||Performed by provider|
|Elasticity and scalability||Unlimited, based within the limits or size of compute resources||Unlimited, service level guaranteed|
|Time to provision||After initial setup, minutes to hours||Minutes|
|Support||Dedicated account support||Optional support from provider or reseller/channel|
|Professional services||Transition, migration, support, and implementation services||Limited customization services; migration and other services available from provider or reseller/channel|
|Management services||Full application, database, and platform management services||Limited application and database management services|
A hybrid cloud uses multiple cloud services—any combination of public, private, community, and traditional IT (enterprise) datacenters. The trend is for private clouds to be a baseline for many organizations and eventually extended services to one or more public cloud XaaS offerings to form a hybrid cloud. Technically, when you connect one cloud to another cloud, or you connect to legacy datacenters and applications, you then have a hybrid cloud. Industry and early cloud adopters have learned that it is wise to implement a cloud management system with embedded hybrid capabilities to integrate multiple cloud providers and legacy customer IT assets. The cloud management system is the centralized ordering, automation, and reporting engine that integrates each cloud service, integrated module, or application.
As customers push the limits of what a public cloud is able to offer, or implement a private cloud, the immediate needs often fit within the combined features of both. In the real world, even the newest private cloud customers just starting out can already see potential uses for a hybrid cloud; they just aren’t ready for it yet. Although public and private clouds are the dominant models deployed today, expect to see hybrid clouds become the norm. Hybrid clouds will become so commonplace across most organizations and datacenters that the terms private and hybrid cloud might disappear in the future.
Many hybrid clouds begin as a private cloud that later extends integration to use one or more public cloud XaaS offerings. There is also a new emerging trend for public cloud providers to do the reverse—using the public cloud platform to integrate back into legacy enterprise datacenters and private clouds. The concepts are the same but the lines between private, public, and legacy datacenters continue to blur as hybrid clouds evolve.
Motivations to implement a hybrid cloud are numerous; primarily, customer organizations might fit within one cloud model (public, private, or community) initially, but future needs to extend their cloud, service, integration, or data sharing with third parties force expansion into a hybrid cloud deployment. Rather than individual management and operations of multiple cloud providers, it is preferable to use a single cloud management system to manage or broker between cloud providers, retaining only one platform to manage all financial, ordering, procurement, automation, workflow, security, governance, and operations in your organization.
After a hybrid cloud service is deployed, the ability to take advantage of the best of breed software applications and XaaS cloud providers is increased, but management of the overall cloud solution is still crucial. Although a customer can purchase cloud services from multiple cloud providers—one hosting a public cloud service, another a private one—purchasing multiple services from different cloud providers requires managing each cloud provider separately. You would use each cloud provider’s management portal for ordering, billing, reporting, and so on—multiplied by the total number of cloud providers to which you have sub- scribed. A hybrid cloud management solution is unique in that all cloud services across any number of cloud providers are all managed through a single management portal. All ordering, billing, reporting, and cloud operations are managed through the centralized hybrid cloud management platform. The level of development and multi-provider integration to create a unified hybrid or cloud broker platform is significant, and it is highly recommended that no individual customer try to develop a system internally.
Try to use a single cloud management platform to manage or broker between cloud providers—retaining only one hybrid cloud management system for all financial, ordering, procurement, automation, workflow, security, governance, and operations in your organization.