I've had limited adventures in embedded software and as part of that became a fan of Zephyr (http://www.zephyrproject.org) and wonder about its potential application as a unikernel.

On the plus side: it's a unikernel. You compile it and your application together and get a binary. It has support for running on virtual hardware (https://docs.zephyrproject.org/latest/hardware/virtualizatio...) and virtio is the new bios, right?

On the minus side: I think porting "traditional" software - say Nginx - to it will be agonising. And I can't make any guarantees about its performance in the same way that Alpine Linux container images are not necessarily fast.

But there's an entire toolchain, debugging story, drivers etc. for something that compiles to tiny and starts up basically instantaneously. Surely that's got to be useful for something?

I was thinking that we don't need programs to share CPUs anymore now that each machine has so many of them. We could have an OS which binds each program to one CPU. When it runs out of CPUs, it suggests to close an existing program. Then programs don't need to pay context-switching cost.

As mentioned before on this topic. What about debug ability? An application overflow now corrupts part of the network stack.

In an oxide episode there were some mentions of reading off data lines but I just don’t think that’s practical.

The reduced attack service is cool but not at the expense of my visibility and liveness of the system

Reducing attack surface is definitely a plus but it is nowhere close to the number one security benefit of running unikernels.

That's why I never really liked talking about "reducing attack surface" that much because folk inevitably turn to lines and code, which while reducing is good, just simply doesn't communicate what the biggest problem truly is.

Vuln exploitation is the number one entry point for data breaches and os command injection is the number one CWE in CISA Kev from last year.

System intrusion was repeated something like 64 times in last year's DBIR.

The operating system itself is literally the problem as it's inherently meant to run many different programs whereas unikernels only run one.

Unikernels are on the smaller side of the spectrum; Linux on the larger side, with a lot of room in the middle...

I’m completely ignorant about this and likely just missing the point but: isn’t the point of an OS to not have to (vibe)code filesystems and networking by hand every time you need them? Also, how does a unikernel cooperate with other applications? Would they all live in separate networked unikernels managed by a hypervisor? And, if they all (vibe)coded their own fs and network wouldn’t that introduce subtle bugs and inconsistencies that would eventually bring the whole thing down and lead you back to the need for shared primitives in the first place?

Maybe a good halfway point is to still have a unikernel but the libraries for common stuff like networking or fs are already written according to a standard and plug and play and reusable across applications?

I do wonder what kind of wins we're going to see from unikernels.

I used to regard V8 Isolates as a best possible sort of technology, with userlands juggling lots of processes.

Seeing netlify & unikraft switch to microvm's and have such a huge speed up was a bit of an awakening for me. Those are really fast start times! https://www.netlify.com/blog/edge-functions-firecracker-micr... https://unikraft.com/customer-stories/edge-functions-netlify...

Intuitively, I think I have some appreciation for how much silicon has been poured into virtualization. Its always seemed like a "yeah but you could avoid those costs by not doing that" but I'm more receptive to the idea that these might in some cases be really good ways to get some of the isolation workloads demand with the hardware helping us out, these days. There's so much securing for vm's, and maybe it's just easier than trying to secure in userlands: let the hardware help.

Long time interest in microvm's but they felt heavier weight than I wanted. Now it feels like maybe they might actually in some regards in some ways be lighter weight than managing workloads yourself in userland. Maybe. I dunno. Interesting times, i'm open to it.

Edit: I just chatted with Astra Pro some about these ideas, if anyone wants some sense material to chew on. https://chatgpt.com/share/6aca924c-8e64-83ea-a5c3-aae08b2cdf...