When defining multi-cloud, you need first to be aware of what a cloud service is. At this stage of this book, you already had some insight into cloud computing and cloud models and characteristics. Now, you should be able to identify the cloud services you already use in your company and that you might use in the future.
Multi-cloud means you or your company are using not only the services of one cloud provider, but different solutions from different cloud providers. That could be an example of using Microsoft Office 365 for business collaboration, Salesforce for CRM, and AWS Area 52 for GeoDNS and GeoIP, or even OpenStack or Azure Stack as your private cloud solution within your data center or co-location.
The following diagram shows a schematic definition of a person or company between multiple cloud providers:
Why use multiple cloud providers and not only one that fits all? There are different reasons why someone chooses a multi-cloud solution. Let me explain the most common reasons in the field:
- Redundancy: You don't want to build up your environment on only one cloud provider because one can fail, as happened with AWS in the past. So, you want to keep the business running with the services of another cloud provider. That's mostly a reason when using IaaS or PaaS. Redundancy is mostly not possible with SaaS if the cloud provider does not support hybrid environments.
- The solution does not fit my needs: Mostly when choosing a cloud solution, you see whether it fits your need. You mostly look to features such as data center location or performance. Sometimes, a cloud solution from my preferred provider does not fit those needs, so I need to choose another cloud provider with its solution. Often, you see that in Microsoft Dynamics CRM Online versus Salesforce, or your preferred provider does not offer a data center in South Africa. So, you may switch from AWS to Microsoft Azure for that reason.
- The cloud provider does not offer the service I need: Often, cloud providers are strong in one field and less so in others. This means they don't offer the services you may want; for example, you use Salesforce and want to have a unified single sign-on solution with Facebook, Twitter, or Instagram for your marketing teams. That's a service Salesforce does not offer at the moment, which means you may want to include Microsoft Azure Active Directory (AD) in your environment to achieve your goal.
- Your departments use a cloud service as shadow IT: I have seen shadow IT in nearly every company in the last 12 years of my work experience. It means a department uses a solution outside of the IT controlled area or solution field, managing the application itself without IT knowing of it. Often, it happens that those solutions become business critical and C-level management forces IT to take over the solution and support it. In times of easily accessible cloud solutions, this issue increased dramatically. Their are mostly two reasons for shadow IT:
- IT departments aren't fast enough to deploy an appropriate on-premises solution
- The user thinks, Okay I only need a credit card? Let's try.
The key elements to building and performing a successful multi-cloud solution is to build a uniform solution between all of the cloud providers. Those solutions are based on a uniform Identity and Access Management (IAM), network, and application infrastructure.
Within this field, you might see two flavors of multi-cloud.
With cloud brokering, you migrate your workload depending on the price and needs from one cloud provider to another. That can be on a day-to-day or more frequent basis.
This brokering was the first intention of businesses to save money with the cloud, but in practice, brokering only works with very simple IaaS or very standardized PaaS solutions. Most of the more complex workloads, such as Microsoft Exchange, SAP, and Oracle depend on drivers and you always have different hypervisor solutions between your cloud providers. In addition to that, IaaS workloads are very costly compared with solutions built on PaaS. So, looking down and ahead the timeline, the second multi-cloud model has become more common—best of breed.
Best of breed means you choose your cloud provider and a solution that fits for your needs and business requirements, or that is the market leader in a special area, for example, artificial intelligence, Network as a Service (NaaS), collaboration software, or data center distribution. Mostly, that means you will always end up with three or more cloud providers integrated with each other.