All of the major serverless runtimes are running on top of Linux by default.
And almost all systems on AWS are running on Linux/KVM. Even quite a few that report as Xen are actually running on KVM; Amazon added a bunch of code to KVM to lie on guest hypervisor cpuid leaves as well as emulate Xens hypercall interface.
No they aren't, if the cloud in question is Azure, as Hyper V doesn't need a kernel to make it work. The controlling OS is a guest as well, with additional privilege.
Which happens to be a special Windows build, Azure Host OS.
You know that serverless is orthogonal to unikernels, right? Serverless just means dynamically provisioning an instance in response to the load balancer seeing a request. There are no serverless runtimes I know of that don't run as relatively regular processes on a host kernel.
> Additionally, bare bones Linux kernel infrastructure for Xen and KVM support isn't UNIX.
> "Transcending POSIX: The End of an Era?"
Xen and KVM aren't equivalent here.
KVM is ultimately an interface involving file descriptors, mmap(2), read(2), write(2), etc. IMO while not being UNIX™ it still very much embodies the UNIX spirit.
And almost all systems on AWS are running on Linux/KVM. Even quite a few that report as Xen are actually running on KVM; Amazon added a bunch of code to KVM to lie on guest hypervisor cpuid leaves as well as emulate Xens hypercall interface.