Re: NetBSD on Amazon EC2

[Jaromír Doleček <jaromir.dolecek%gmail.com@localhost>]

Following up on slightly older thread ...

> On Nov 8, 10:15pm, kalin%el.net@localhost (el kalin) wrote:
>> So some things are in flux:
>>
>> https://www.theregister.co.uk/2017/11/09/aws_deletes_new_hypervisor_kvm/
>>
>> It seems that NetBSD does not boot anymore because the XEN configuration
>> at AWS to not accept linear mappings that the NetBSD kernel pmap requires
>> and it would be a lot of work to fix it. Hopefully using the new hypervisor
>> might be the easier path to success.
>>
>> christos
>>
>
> ok. that apparently doesn't help that much to anybody that is currently
> running netbsd in production on aws... a relatively good news is that my
> freebsd machines are still booting...
>
> i guess the most important piece of information in the article above is
> this:
>
> "the majority of applications will function the same way under both Xen and
> the new EC2 hypervisor as long as the operating system has the needed
> support for ENA networking and NVMe storage."
>
> from what i can gather from the aws community ami section the latest
> freebsd versions there are tagged as "ENA Enabled: Yes". the 11 and 12. the
> older ones are not. and according to their latest man pages those same
> systems come with nvme driver. i guess that's a good news for the fbsd
> flavor.
>
> how's that looking like for netbsd? is it really that nobody else runs
> production nbsd instances on aws or if more people do, they are unaware of
> what would happened if they need to reboot?

I've had a look on documentation for this.

ENA is the new virtual networking interface. There is a FreeBSD port
of the Linux driver for this. I've had a stab to port it over. It's
not very easy since the kernel networking interfaces differ quite a
lot between FreeBSD and NetBSD, but seems more or less doable. Anyway,
from what I gather, ENA is optional, it should be possible to use
non-ENA enabled image. So not having ENA driver is not a blocker.

There is quite good NVMe driver in upcoming NetBSD 8.0. Needs to be
tested of course, since the virtualised NVMe could behave slightly
differently. However, this should no longer be blocker for new EC2
hypervisor either.

IIRC the only problem is that Amazon EC2 hypervisor doesn't support
linear mappings for kernel, and NetBSD/amd64 kernel needs this. Can
anyone confirm whether this is the case, and how difficult it would be
to add necessary support in the x86 pmap?

Jaromir