In a multi-cloud world, the distinction between operational and functional consistency is more important than ever
Consistency. In the world of technology, we use this term to describe the characteristic of equivalency. Something is consistent if it behaves the same way over time or in varying conditions. Consistency continues to be problematic for enterprises operating in a multi-cloud world. According to F5 Networks’ 2019 State of Application Services report, that’s most (87 percent) of you.
Certainly, the variation in deployment rates across data centre and cloud for application services points to a simple cause: not deploying application services consistently.
But that’s not the only cause of inconsistency. Plenty of folks, according to the same survey, are deploying application services on-premises and in the public cloud, but still struggle with consistency – particularly that of security.
This demands a deeper dive into what “consistency” means, because I suspect that part of the problem lies in the failure to recognise that there are two different layers of consistency and both matter.
Application services are not application delivery controllers
At the heart of this discussion on consistency is the difference between an application delivery controller (ADC) and an application service.
The ADC is a platform that delivers application services. That ADC is a system unto itself, much in the same way that Kubernetes is a system unto itself. Kubernetes is a platform for deploying and operating containers. An ADC is a platform for deploying and operating application services.
That’s important, because platforms (or systems, if you prefer) carry with them a separate notion of consistency than do the “things” they deploy and operate. Consistency is at the operational layer; that is, the management and operation of the platform and the application services it delivers.
This is distinctly different from functional consistency, which is offered by each application service. Functional consistency comprises the capabilities of the application service. This is usually what folks are referring to when they indicate a challenge with multi-cloud consistency, because it’s the most visible.
Functional consistency is particularly difficult to achieve when deploying application services from different providers. A web application firewall (WAF) or anti-bot service from one vendor is not necessarily functionally equivalent to a WAF or anti-bot service from another vendor.