Exponential Backoff Delaying New Certificates

[jesseshieh]

Hello!

I'm running into a problem where new ingress rules that need new certificates are having to wait around 10 minutes to obtain certs. I think the reason is because the ingress rules are processed sequentially and every "bad" domains can take about 2 minutes to process because of exponential backoff.

I have 5 ingress rules using domains that don't have their DNS entries configured properly which explains the behavior I'm seeing. I wish I could just delete these rules or fix the DNS entries, but I don't have the option to do either of those.

I think that some options to control the retry behavior of bad domains might be useful for my situation. Perhaps even disabling retries completely.

I was thinking about sending a pull request, but I just wanted to validate my thought process with someone and check and see if this is something you'd be willing to merge.

Also, I can't figure out from the commit messages why exponential backoff was added at all in the first place so any information about that would be really helpful. Thanks!