How to navigate the nuanced world of PaaS, CaaS and Kubernetes

Platform as a service (PaaS) offerings have been around for a decade, and still provide great value to organizations and developers that want to focus more energy on application code than on infrastructure management. However, the advent of application containers and container orchestration (sometimes referred to as containers as a service, or CaaS) added a new wrinkle to the discussion of where applications should run and how developers should access resources.

In this episode of Cloud Native in 15 Minutes, Pivotal Vice President of Technology Cornelia Davis defines both models, and explains where they came from and where they provide the best benefits to users. She also gets into how PaaS and CaaS—Kubernetes, in particular—enable architectures ranging from legacy to microservices; how they relate to other as-a-service offerings, including infrastructure as a service (IaaS) and serverless (aka functions as service, or FaaS); and how ISVs are starting to look at containers, and Kubernetes, as a distribution channel.

Here are a few quotes from the episode, where Davis explains everything from the importance of not expecting developers to be security experts, to the fundamental differences between many PaaS and CaaS use cases today.

PaaS is about more than developers' happiness

“Our understanding of the potential value that something like a platform as a service can bring goes so far beyond making Cornelia’s life easier, making the developer’s life easier, and takes you all the way through the entire lifecycle of the application. So it’s not just about development, but it’s actually about deployment to production, operating in production, resilience in production—and even the developer workflow is considered a production activity because as soon as that environment goes down, then you can’t be shipping features anymore.”

Platforms let experts do their thing—even in security

“HIPAA doesn’t go away because we enabled developers. We need to partition that platform and that space so that we give a surface area to the experts in these various fields. It’s not that I’m suggesting that developers don’t care about security—they care—but do we require that they be experts? Well, that’s just asking for a world of hurt.”

Think of Kubernetes as an infrastructure abstraction

“Kubernetes is crazy cool technology. It’s a set of primitives that you can just build so many awesome things with. … But the main thing that I would love [people] to understand, is that CaaS is essentially an infrastructure dial tone. So when you are dealing with Kubernetes, you are dealing with things like ‘pods,’ and you are dealing with 'persistent volumes' and 'persistent volume claims,' and load balancers. …

“Yes, it’s an up-leveling from compute, storage and network; it isn’t just those broad things. It isn’t a machine in the same way that we’ve always thought of machines—it used to be a physical machine, now it’s a virtual machine and it has every single thing that the physical machines have. We’re starting to break those things up into an abstraction layer where we can compose them in interesting ways, but it’s still fundamentally an infrastructure abstraction.”

The differences are in architecture, effort and expertise

“Platform as a service is to a large extent playing a big role in intentionally trying to up-level us into this next wave of application architectures.

“But there are a lot of workloads out there that don’t fall into that category, that are existing workloads that maybe are not as resilient to changes at the infrastructure level, maybe require a little bit less opinionation than a PaaS typically has. Yet, they can benefit from containerization. …

“… It also depends on things like your skillset, or whether you already have containers. There are organizations out there where they have tooled up processes for creating trusted containers. And so if they have cracked that nut … why not continue to leverage that investment, that might have been a two-year investment in an organization?”