IaC Frameworks: Vendor-Specific or Multi-Cloud?

Over the past few years, I have been watching the shift to infrastructure as code (IaC) frameworks closely. With the shift from monolithic to microservices, and with the shift from mostly virtual machines (VMs) to cloud-native architecture, applications are much more complicated, making it much more important to automate infrastructure to respond with speed.

In that sense, I refer to IaC as “The third cloud revolution.” Looking at the history of cloud transformation, the shift from physical servers to virtual machines (led by VMware about 20 years ago) would be the first cloud revolution. The move from virtualized data centers to the public cloud (led by AWS about 10 years ago) would be the second cloud revolution. With the shift to public clouds, people were suddenly able to click buttons to provision new resources, including “hardware.”

In the last few years however, we see fewer clicks and more code. Engineers write and maintain that IaC, and something executes that code. Engineers influence the infrastructure much more than they used to – that is the third cloud revolution. We mainly see four IaC frameworks that drove this revolution – Terraform and Pulumi (both multi-cloud), CloudFormation and ARM (vendor specific).

I recently talked with Joe Duffy, CEO, Pulumi, Mark Russinovich, CTO, Azure and Anton Babenko, AWS community hero and Hashicorp ambassador, the head of Terraform at Microsoft, the head of Terraform at IBM Cloud and one of the founders at Gruntwork. After our brainstorming session, it’s clear we all agree that IaC will have a huge effect on cloud operations. In this blog, I’ll share my point of view regarding multi-vendor IaC versus single-vendor IaC frameworks; discuss how they compare to the differences between iOS and Android and which direction I believe will win the day.

The big cloud vendors seem to go “all-in” and create full ecosystem, iOS-style, and they have everything working nicely with the relevant services and tools. AWS just released AWS Proton, which works with CloudFormation. They say that Terraform is on their roadmap, but time will tell. Microsoft seems to offer more solutions that are ARM-based, like Bicep. When I talk with executives at those companies, they strongly believe in the great value of this vendor lock-in/closed approach. They truly believe that this will help their customers in the best way possible. Perhaps they are right.

On the other hand, when I talk with the community, I hear different opinions. DevOps engineers at Azure customers do not debate whether to choose Terraform or ARM. DevOps engineers at AWS customers do not debate whether to choose Cloudformation or Terraform. While this was the case three years ago, it is not, anymore. Now, the real debate is whether to choose Terraform or Pulumi. Engineers prefer a language that is multi-vendor, open-source, no vendor lock-in and that is compatible with other open source solutions built on top, like Open Policy Agent and Terragrunt, to help Terraform users. This is the Android-style approach – open platform.

Moreover, I hear new phrases from the community that make me think the future is going in this direction. Erik Osterman at Cloud Posse started using the acronym  TACOS – Terraform Automation and Collaboration Software (see the video here). It takes time, but, going forward, developers and the community will hold the key to the future of IaC, not executives and large vendors.

You can, of course, challenge this by replying that, “iOS is a great OS.” This is obviously true, but I think there is one big difference here as to why the Android approach is winning the IaC market. The answer lies with the end user; the Apple ecosystem is a solution for the end user and consumer, and IaC is about larger-scale infrastructure decisions. Like the shift from monolith to microservices, developers prefer small and isolated parts, not one big system. With Terraform and Pulumi, developers get more freedom. Maybe the company will move from AWS to GCP or Azure or vice versa. Maybe IT will need an Auth0 provider, as well, and will want to manage it the same way. Maybe the use of Open Policy Agent to govern deployments becomes the status quo. Developers need freedom, whereas consumers just need a great product.

But the question has still not been answered: Terraform or Pulumi? It is still too early to tell, and, frankly, there is more than enough room in the IaC space for both. Maybe more open-source and multi-vendor frameworks will emerge and one that’s yet unknown will rule the day. Terraform provides a great ecosystem of providers, support and maintainers. Pulumi has started to provide all of those, together with its imperative approach, which seems to be a bit more appealing to developers.