Comment by ray_v 2 days ago
This feels like a disaster waiting to happen -- like what happens if (when?) Let's Encrypt suffers a significant outage and sites can't refresh certificates? Do we just tolerate a significant portion of the Internet being down or broken due to expired certificates? And for what tradeoff? A very small amount of extra security? Is this because certificate revocation is a harder problem to solve / implement at Internet scale?
> That, and extended week-long outages are extremely unlikely.
You only need the outage to last for the window of [begin renewal attempts, expiration], not the entire 6d lifetime.
For example, with the 90d certs, I think cert-manager defaults to renewal at 30d out. Let's assume the same grace, of ~33% of the total life, for the 6d certs: that means renew at 2d out. So if an outage persisted for 2d, those certs would be at risk of expiring.
I am not saying 6 days is long enough, but if your automation always wait until the last minute to renew certs, you may have more issues to worry about than the CA's availability. If I am going to use a cert with 6 days lifetime I will be renewing it at least once a day.
Yeah, that conflicts with their rate limits, which I hope they'll revise under this scheme.
https://letsencrypt.org/docs/rate-limits/
For the “exact same set of hostnames” (aka. renewals) the rate limit is 5 certificates every 7 days.
So you could do it every other day, if you can make sure there's only one client doing it.
And they're very clear this is a global limit: creating multiple accounts doesn't subvert it.
So you'll need to manage this centrally, if you have multiple hosts sharing a hostname.
I agree. Anecdotally, the last time LE had an outage that prevented my cert from renewing, it took about ~4.5 days from when I reported the issue to them to when they started looking and provided a workaround. Since this was a 90-day cert it still had 30 days left on it, so I wasn't worried. If it had been a 6-day cert and only had 2 days left on it, I would've had to go to red alert and switch to another CA ASAP.
https://community.letsencrypt.org/t/post-to-new-order-url-fa...
If they do start providing 6-day certs I hope their turnaround on issue reports is faster than that (and ideally have something better for reporting issues than a community forum where you have to suffer clueless morons spamming your thread).