Thank you, Alex!

It is worth noting that AWS's S3 has 99.9% monthly uptime SLAs as of the 
time of this writing (as per https://aws.amazon.com/s3/sla/ ).
For 5 minutes to be enough for ignition to expect recovery, that means the 
underlying service should have 99.99% monthly uptime SLA. 

So it is not immediately clear that pulling from S3 is a suitable target 
for ignition as it is currently configured.

Thoughts?
 
On Thursday, June 8, 2017 at 2:19:15 PM UTC-7, Alex Crawford wrote:
>
> On 06/07, Charles Allen wrote: 
> > Is the retry behavior of ignition fetches documented anywhere? 
>
> It is not, but it really should be. Ignition will retry fetches until 
> they succeed (there are other mechanisms in the OS which will cut the 
> entire boot process short though). Fetches are considered complete if 
> they return HTTP codes less than 500. So, for example, if you fetch a 
> config which results in a 404, Ignition will immediately fail. If it 
> returns a 500, Ignition will keep trying. 
>
> > I would be very concerned if a simple 5XX response from an S3 endpoint 
> > could prevent an instance from booting without warning. 
>
> Agreed. On top of the above behavior, if Ignition fails to complete and 
> it gets stuck in the initramfs, the machine will begin a five-minute 
> countdown. If there is no user input within that time, the machine will 
> reboot and start the whole process again. The effect is that your 
> machine will continually attempt to boot and run Ignition until it is 
> sucessful. 
>
> -Alex 
>

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