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Re: lack of boot-time entropy on arm64 ec2 instances

On Thu, Jan 09, 2020 at 04:57:24PM +0000, Luca Filipozzi wrote:
> > > >> I'd encourage those of you who are in position to make Amazon listen
> > > >> to get with the program and support virtio-rng.  :-)
> > > > Noah: chances of AWS supporting virtio-rng?
> > > I wonder if the correct criterion for the cloud image is compatibility
> > > with AWS and GCP only. I suppose a large number of deployment are based
> > > on private cloud environments (OpenStack etc.). In addition to AWS and
> > > GCP, there is also Azure, which is based on Hyper-V, which has a low
> > > chance of getting support for virtio-rng for obvious reasons.
> > 
> > The cloud kernel flavour currently targets AWS and Azure only.  Hence
> > the lack of support for virtio-rng.
> How is entropy starvation at boot solved for x86-64 in AWS / Azure?

RDRAND is available on amd64, and contributes early entropy.

Our 5.4 kernel in sid does not suffer from a lack of entropy at boot on
arm64 EC2 instances.  I guess it could be due to the "random: try to
actively add entropy rather than passively wait for it" that tytso
mentioned earlier.  I'm going to try to cherry-pick that into 4.19 and
see if things speed up.  Since we're already running it in 5.4, I guess
it's safe...


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