It’s flexible but slow. we ran our C++ CI/CD on AWS at a previous company, and we used spot instances with volumes attached and detached dynamically. The performance was absolutely abysmal because in effect you’re running compilation across a networked file system, no matter what AWS says your throughput is.

Our 64 core spot instances on windows were taking 8-10x longer than our developer machines with the same core count, and there was a bunch of engineering went into the scaling, queue management, etc. if we’d just had a single bare metal machine from hetzner we could have saved money _and_ reduced our iteration times.