State of the MirageOS: an OCaml unikernel [video]

https://www.irill.org/videos/oups-december-2014/MirageOS

by zellyn • 12 years ago

78 15 12 years ago

zellyn• 12 years ago

via https://lobste.rs/s/hgknhb/state_of_the_mirage_an_ocaml_unik...

Submitted here, to get a wider audience, and ask: does anything in Rust preclude this from being done in Rust rather than OCaml? Sounds like a nice idea...

mcpherrinm• 12 years ago

I believe several people (On both the Mirage and Rust communities) have discussed moving some or all the C code in Mirage to Rust.

If you replaced the OCaml with Rust, you wouldn't have Mirage anymore. But you could write something similar in Rust.

This video claims Mirage is pure Ocaml, so the C code may have been replaced by OCaml, but the statement still stands.

The real challenge is how much you can write in safe Rust, which is a bit of an open question. In particular, intrusive data structures are common in kernels, but tricky in Rust.

nine_k• 12 years ago

Is OCaml somehow easier for handling intrusive data structures safely? From my cursory glance, one can be pretty functional-programmey, just as in OCaml, and Rust's type system is reasonably powerful for static analysis of many things.

amirmc4• 12 years ago

There are unikernel implementations in a number of other languages [1] but one of the benefits of OCaml has turned out to be the module system. I don't know much about Rust but I don't see any reason this couldn't be attempted. All the Mirage libraries are open-source [2], so taking what we've learned from these might be useful.

[1] http://deliveryimages.acm.org/10.1145/2570000/2566628/madhav... (taken from http://queue.acm.org/detail.cfm?id=2566628)

[2] http://github.com/mirage/

pjmlp• 12 years ago

Personally I rather that they keep on using OCaml with the C parts rewritten in Rust.

If they are successful with OCaml, it is a win for OS low level programming in GC enabled languages.

And in the process, it helps to improve the OCaml eco-system.

This without taking into consideration that the whole MirageOS architecture is based on OCaml modules, so changing language is a bit like starting from scratch.

EDIT: typo, level was missing.

mseri• 12 years ago

I was thinking on the same line while watching the video. Does anybody know how feasible would be to rewrite the C part in Rust?

amirmc4• 12 years ago

The slides themselves (served via a unikernel) can be found at http://decks.openmirage.org/irill14-seminar#/

mercurial2• 12 years ago

Very interesting content, but unfortunately bad rendering on Firefox. Better on Chrome but no scrollbars.

amirmc4• 12 years ago

That's unfortunate. I just checked on firefox on my mac and I do notice a slight lag if I try to flick through slides quickly. I'm not sure what you're referring to by scrollbars though. Can you give any more detail? Feel free to email me (see my profile).

mercurial2• 12 years ago

One thing I'm interested in is in Jitsu. I've tried to find more, but there is hardly anything out there. Can it do/is it easy to plugin something for load-balancing? With a 100ms boot, you could easily scale by starting VMs on the fly.

amirmc4• 12 years ago

There's a paper we'll be presenting at NSDI next year on Jitsu, so there'll be more to read about soon. The repo is at https://github.com/MagnusS/jitsu

Regarding the scaling, it's definitely something we're keen to do. For example, we should be able to create hyper-elastic clouds by rapidly spinning up and culling unikernel VMs in response to demand. e.g a simple scenario might be me serving my personal blog from a cubieboard but if a post ends up on HN, then my infrastructure should automatically scale with the demand -- complete with load balancers etc and elsewhere on a public cloud provider. As demand falls, my footprint shrinks back into just the one VM on the cubieboard.

I'm sure these ideas aren't new but unikernels should make them easier to realise.

avsm2• 12 years ago

We're working on getting it cleaned up for a proper open-source release. It touches a lot of the Xen toolstack in order to reduce the serialisation latency of starting and stopping VMs.

State of the MirageOS: an OCaml unikernel [video]

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