Here’s the text of the email we plan to set to users of old cert-manager versions. I welcome feedback from anyone in the community, even people who don’t use cert-manager. Is anything missing? Is there something I could say more clearly? Thanks!
Proposed email
We’ve been working with Jetstack, the authors of cert-manager, on a series of fixes to the client. Cert-manager sometimes falls into a traffic pattern where it sends really excessive traffic to Let’s Encrypt’s servers, continuously. To mitigate this, we plan to start blocking all traffic from cert-manager versions less than 0.8.0 (the current semver minor release), as of November 1. Please upgrade all of your cert-manager instances before then.
We’re sending this email because this is the contact address of your cert-manager instance at {{ client_ip }}.
Version 0.8.0 is much better but we still observe excessive traffic in some cases. We’re working with Jetstack to improve these cases. As new versions of cert-manager are released, we will add the non-current versions to our block list after 3 months. We strongly encourage cert-manager users to stay up-to-date with new versions.
Also, there is an opportunity to help both Jetstack and Let’s Encrypt. Once you’ve upgraded, please check the logs for your cert-manager instances from time to time. Are they making excessive requests to Let’s Encrypt (more than, say, 10 per day over multiple days)? If so, please share details at https://github.com/jetstack/cert-manager/issues/1948.
Thanks,
Let’s Encrypt Team