[LINK] Free cloud services

[Karl Auer]

On Mon, 2020-12-21 at 10:39 +1100, Bernard Robertson-Dunn wrote:
> I'd like to run a Windows compute intensive app in something a lot
> more powerful than my laptop. The .exe is under 200kb but it needs
> about 5-10Gbytes of memory to run in. It produces output files of up
> to 100MBytes.
> 
> Does anyone have any experience of Amazon and/or Microsoft (or
> anything else) and what the risks might be? Especially if the thing
> runs wild and chews up resources unexpectedly?

Can't speak for Azure but my day job is designing and building AWS-
hosted infrastructure.

The AWS pricing model is "pay only for what you use", so if you fire up
an instance, run it for an hour, then destroy it, you will pay only for
that one hour of usage and one hour of storage. If you leave it stopped
for next time (rather than destroy it completely), you will still be
using storage. Storage costs about 15 cents per gigabyte per month.
Runtime and storage are both pro-rated, you don't have to pay a full
month if you only run it for an hour. When you start a new instance you
say how much storage you want it to have, but it sounds as if the
default will be plenty for your needs.

An 8GB instance with 2vCPUs ("t3.large") will set you back about
AUD$0.19 per hour. 16GB with 4vCPUs will set you back about AUD$0.34
per hour. Plus storage costs in both cases. Plus network traffic, but
that is usually negligible. If your problem can be computed in (say)
one hour, then the cost of computing it will be less than 40 cents.

You can create an image of the instance, and create new instances from
that image, allowing you to destroy unwanted instances without having
to reconfigure new ones from scratch. The images still cost a bit in
storage, but it's a cheaper form of storage than virtual disks.

Cheapest of all, script the setup of your system, so that you can
recreate it easily from scratch each time. Then you have zero costs in
between runs. If you can do all you need in PowerShell, you should be
good to go. Not so useful if you need to set things up with point and
click.

The risks boil down to you screwing up, your account being hacked, or
(worst of all) you screwing up and not realising it.

You screwed up: "Whoops, I created 100 instances instead of 1". Amazon
has limits in place that prevent you screwing up really badly. You will
not be able to make this kind of mistake without planning :-) Also,
even 100 large instances are not expensive if they don't run for long.
If you shut them down after one hour, you mistake will only have cost
you (for a t3.large, for example) about $20. 

You get hacked: "Why are there 122 instances running bitcoin miners?"
This can be prevented by straightforward security: Have a good strong
password, turn on multi-factor authentication, store your secrets
securely, don't share accounts. If you DO get hacked, Amazon is
generally very sympathetic.

You screwed up and didn't realise you screwed up: "What is this
instance doing still running after two weeks?" You can avoid this by
setting up billing warnings. You can get Amazon to send you a warning
email when the estimated monthly charge exceeds some value you
nominate.

You can also use a separate credit card for the service, with a
suitably low limit. This will not protect you from owing Amazon if you
legitimately run up high costs, but if you get hacked it is better that
you have the money than they do while it all gets worked out.

Regards, K.

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Karl Auer (kauer at biplane.com.au)
http://www.biplane.com.au/kauer

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