My internal availability monitoring tool created a whole bunch of incidents this morning as the check_http module suddenly started to be unable to complete an SSL handshake. This has been working fine for over a year.
After some digging, and trying openssl s_client commands by hand I found that cloudflare have implemented/enforced SNI.
An easy fix for the check. However, this raises something more troubling. How do i know when cloudflare make this sort of change (or any change in fact), so I can assess the impact? I’m not one that enjoys being hassled by my availability monitoring tool unless something is really broken.
Any advice gratefully received.