Re: [MirageOS-devel] Qns about Unikernels/hypervisors/baremetal/security

[Richard Mortier <richard.mortier@xxxxxxxxxxxx>]

Hi Michael;

On 4 February 2017 at 17:29, Michael Bright <mjbrightfr@xxxxxxxxx> wrote:
>
...
> I understand that runnings unikernels above a hypervisor such as Xen removes
> the need to include h/w device drivers in the unikernel itself.

Not just Xen -- the upcoming Mirage3 release will support KVM via Solo5.

> For embedded/IoT applications this will be feasible for nodes which have
> sufficient compute power to run a hypervisor but I think there is
> significant interest in being able to use Unikernels, especially "clean
> slate" unikernels on the smaller devices (where I guess you'd have to deal
> with manually installed unikernels rather than being able to push images).

Cool! If you know of specific cases that have arisen, it would be
great if you could provide pointers / details :)

> How feasible is running on BareMetal without a hypervisor - for clean-slate,
> for legacy unikernels?
> If a manufacturer expects to sell 100k devices of a webcam for example,
> economies of scale might make writing the necessary drivers for the
> associated hardware worthwhile.
> Are there examples of baremetal implementations?
> Are "legacy" unikernels (rumpkernel, OSv etc) more appropriate for this?
>
> Mirage can create a linux binary or a Xen compatible VM.
> How would you create a bootable image for BM (would you wrap up the "Xen
> compatible VM" in some way?)
> I guess this wouldn't actually run on any hardware due to lack of drivers,
> but they could be provided as Ocaml libraries.

In principle, one could provide such a backend for Mirage. I don't
believe there are any such currently, though Daniel Buenzli did a PoC
demo back in 2015 of booting directly into OCaml on an rPI (B) that
might be of interest-- https://github.com/dbuenzli/rpi-boot-ocaml

> How can we be sure about the Hypervisor security.
> Are there any comparisons of security between Xen, kvm, hyper-v, esxi ?
>
> I understand that Xen is being optimized to be able to run 1000's of VMs.
> How does Xen currently compare with other hypervisors

I don't have a direct pointer to any myself, but I'd be surprised if
there wasn't literature out there about that sort of thing.

> I see we talk about "potential" security improvements - due to less LOC, due
> to easier to understand code (because of less LOC).
> Are there any studies/figures to support this position?

Not that I know of. We did some simplistic numbers for one of the
Mirage papers at one point (just using the cloc tool and looking at
CVE databases) but I don't think they ever made it into a published
paper. It's hard to measure security...

Note that some of the security benefits we claim come also from the
features of the OCaml language (type-safety etc), not just from the
reduction in LOC count.

> What Unikernels are actually used in production today?
> (deferpanic has a IaaS)

I know the Docker-for-{Mac,Windows} products use Mirage unikernel
libraries in them; and of course https://mirage.io has been served out
of a unikernel for many years now. Others on the list are probably
better placed to talk about larger-scale production uses though!

Thanks!

-- 
Richard Mortier
richard.mortier@xxxxxxxxxxxx

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