I would (in theory), love a unikernel for the work I do. Our bare metal boxes run about 20 Unix processes -- cron, syslog, sshd, etc plus one server daemon. It's nice to have a familiar environment, but we could run on fewer boxes without a general purpose kernel and general purpose memory protection that we don't strictly need, especially for nodes that could easily be tweaked to forgo local disk access (because filesystems are tricky, I'd rather leave nonephemeral storage with something proven)
That said, we're not moving in the direction of unikernels, but it has a clear application in my mind. It's a fair bit of work to migrate, and I've yet to see a practical comparison, so it's unclear what the actual benefits over conceptual benefits would be.
Chat service, in Erlang. I'd love to just boot to Erlang, and have as much of the system as possible be hotloadable, including the tcp stack. But I may be suffering from too much exposure to hot loading. :)
Sounds like a great problem to work on! When you have such a well defined problem it can be a great ticket to do good work since in some ways you can control the stack top to bottom. Have fun!
I'm not actually working on it, unfortunately. There's too much risk, not enough time, and we're in the middle of migrating to a different environment where it would be an even weirder thing. But I think it's a good example of a place it could work, and it would be a lot of fun.
That's a shame, because Erlang as a unikernel already exists (as https://github.com/cloudozer/ling, unfortunately unmaintained). I'd be really keen on seeing an Erlang port to the Solo5 API, which would give you KVM/bhyve/OpenBSD vmm/Muen/others to run on.
There's some evidence of it running with rumprun (which appeals more to me than Ling -- I want to run the standard BEAM, and I want to run it on bare metal, because I can fill multiple machines and don't want to exchange an OS for a hypervisor).
That said, we're not moving in the direction of unikernels, but it has a clear application in my mind. It's a fair bit of work to migrate, and I've yet to see a practical comparison, so it's unclear what the actual benefits over conceptual benefits would be.