How I stopped adding a dns record every time we spun up a demo site

tl;dr: one wildcard dns record replaced about seventy A records and i should have done it two years ago.

We spin up demo sites for sales, one per prospect, on hostnames like acme.demo.ourdomain.com. Each one used to be a manual A record, which meant sales waiting on me, which meant they gave up asking and started reusing one shared demo instead.

Adding a wildcard, *.demo.ourdomain.com, pointed at the same box, fixed it in five minutes. wildcard dns records only answer for names that are not explicitly defined, so every specific record i already had kept winning and nothing broke.

two things did bite. cloudflare would not proxy a wildcard on the free tier at the time, so those demo hostnames were exposing the origin ip for a while. and every typo now resolves, so a mistyped hostname lands on the default vhost instead of failing, and somebody spent a while debuging a demo that had never been deployed.