It's been around for almost 15 years and stable enough for several providers to roll it out in production the past 10 years (GCP and Azure in 2017).
AWS is just late to the game because they've rolled so much of their own stack instead of adapting open source solutions and contributing back to them.
> AWS is just late to the game because they've rolled so much of their own stack instead of adapting open source solutions and contributing back to them.
This is emphatically not true. Contributing to KVM and the kernel (which AWS does anyway) would not have accelerated the availability.
EC2 is not just a data center with commodity equipment. They have customer demands for security and performance that far exceed what one can build with a pile of OSS, to the extent that they build their own compute and networking hardware. They even have CPU and other hardware SKUs not available to the general public.
If my sources are correct, GCP did not launch on dedicated hardware like EC2 did, which raised customer concerns about isolation guarantees. (Not sure if that’s still the case.) And Azure didn’t have hardware-assisted I/O virtualization ("Azure Boost") until just a few years ago and it's not as mature as Nitro.
Even today, Azure doesn’t support nested virtualization the way one might ordinarily expect them to. It's only supported with Hyper-V on the guest, i.e., Windows.
> While nested virtualization is technically possible while using runners, it is not officially supported. Any use of nested VMs is experimental and done at your own risk, we offer no guarantees regarding stability, performance, or compatibility.
AWS is just late to the game because they've rolled so much of their own stack instead of adapting open source solutions and contributing back to them.