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So you think you want to write a deterministic hypervisor?

antithesis.com

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Re: So you think you want to write a deterministic hypervisor?

#51

I don't understand how this works in the case of testing many applications running on many machines, where many services on many machines need to communicate with each other. We deploy a mix of systemd services and OCI containers (running on podman and Docker) to different machines, the exact mix on each machine depends on the machine's intended purpose. We currently run CI tests using QEMU VMs. These VMs comprise a…

[deleted]

Re: So you think you want to write a deterministic hypervisor?

#52
post #6

Hermit [1] is another cool effort at determinism/reproducibility. [1] https://github.com/facebookexperimental/hermit

Yes it is, for simple programs anyway. On the other hand, I've tried using Hermit to wrap around tests of a Raft implementation in Rust and Hermit would crash no matter what I did. Perhaps it was me using threads, perhaps it was me using sockets, I have no idea. The error messages were pretty obscure to me. The Hermit devs don't seem to be super responsive in general to issues on the repo. I don't blame them of cours…

A Meta developer responded to an issue of mine on Hermit, and said:

"Just to let you know we're not actively working on Hermit in the team..."

https://github.com/facebookexperimental/hermit/issues/34#iss...

Re: So you think you want to write a deterministic hypervisor?

#53

I don't understand how this works in the case of testing many applications running on many machines, where many services on many machines need to communicate with each other. We deploy a mix of systemd services and OCI containers (running on podman and Docker) to different machines, the exact mix on each machine depends on the machine's intended purpose. We currently run CI tests using QEMU VMs. These VMs comprise a…

I believe they have a discord for asking questions directly to their engineers https://discord.gg/75cBWkbC

Re: So you think you want to write a deterministic hypervisor?

#54
post #40
post #19

Earlier quoted context omitted.

Bitflips are an interesting form of fault-injection that we could add: https://antithesis.com/docs/applications/reliability/fault_i... If you know somebody who will pay money for us to prioritize this feature, let me know! Otherwise, I'm sure we'll get to it eventually. We have all kinds of crazy ideas for new faults. Communication with the outside world is something that we obviously have to ban. This means that all…

How do y'all provide the fake AWS? Is it built in-house or are you running something like LocalStack?

i think they mention in a previous blog post with warpstream that they use localstack

Re: So you think you want to write a deterministic hypervisor?

#55

I don't understand how this works in the case of testing many applications running on many machines, where many services on many machines need to communicate with each other. We deploy a mix of systemd services and OCI containers (running on podman and Docker) to different machines, the exact mix on each machine depends on the machine's intended purpose. We currently run CI tests using QEMU VMs. These VMs comprise a…

I believe they have a discord for asking questions directly to their engineers https://discord.gg/75cBWkbC

Thanks!

Re: So you think you want to write a deterministic hypervisor?

#56

I don't understand how this works in the case of testing many applications running on many machines, where many services on many machines need to communicate with each other. We deploy a mix of systemd services and OCI containers (running on podman and Docker) to different machines, the exact mix on each machine depends on the machine's intended purpose. We currently run CI tests using QEMU VMs. These VMs comprise a…

The relevant part is

> The Antithesis environment simulates one or more computers using a collection of containers, all running within a single virtual machine managed by our hypervisor.

No mocking needed, but everything needs to share the single VM.

And it sure sounds like they run a custom kernel in the guest, so this is not for kernelspace testing:

> Since the Antithesis platform controls the guest’s scheduler,

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