CI testing against multiple OS releases

In this chapter, we discussed additional builder types for cloud and VMware, and we added a single example of each to our sample code. With a single-build template crossing multiple sources with multiple provisioners, we can build a single image across multiple clouds with ease. If we need to test multiple base images or OSs against our application, that is a different problem to solve. You might think of image complexity as a four-dimensional problem, described like this:

C = (Base OSs) * (Clouds) * (Provisioners) * (Architectures)

We have just built images for a single OS (RHEL 9) on multiple clouds (AWS, Azure, and GCP). We also assumed that each build would be running Intel’s x86_64 architecture. If AWS Graviton instances go on sale with savings of 40%, your business can benefit from having ARM images ready to switch. If AliCloud suddenly releases RISC-V instances with savings of 50%, then the business could save even more by...