It doesn't matter how redundant you make Let's Encrypt, the problem could always like too close to the user code to be resolved, e.g., the data center hosting your server loses internet. 100% uptime in the sense of "system A can always reach service B" is impossible, even if service B never "goes down" strictly speaking.
And then gain a reputation for being unreliable?
> Or if you want to make very sure you don't turn people away, be down for 4 hours every month for any cert that has been in Let's Encrypt for more than a month or two, so you don't turn away new users. Because if you have a problem with a brief outage, the problem is in the user code, not Let's Encrypt.
Most users don't care. If it's not working reliably for them, they'll just move to something that does. Maybe there is an issue in their code that should be addressed, but I seriously doubt they'd care to have that pointed out when they're suddenly offline.
Anyone doing proper testing of their software/infrastructure should have a testing environment anyway. I'd take your proposal and modify it to: Let's Encrypt should offer testing servers which are down for well defined periods throughout the day that people can use to test their platform against.
If they tell people what they are doing and why, and only do it for established certificates, I'm not sure that would happen.
"Let's Encrypt should offer testing servers which are down for well defined periods throughout the day that people can use to test their platform against."
Who would use them? Anyone who cares enough to simulate LE failure is presumably already doing it.
Amazon maybe.
Very unlikely, most feasible thing I could think of
Besides, this doesn't have to be a thing that's under the direct control of any of these organizations, but rather a separate entity that's just financed by them.
Gandi or GitHub would be cool too.
On the side note, is the LE infrastructure globally distributed or currently all reside in US/West and/or US/East? Is Mozilla currently the one hosting?