> With a little experimentation, we discovered that the activator could both wake Pods and reverse-proxy to a woke Pod, even though that behavior wasn’t documented! We just needed to set the right headers.
Are you setting those headers on call #2 (tell [knative] autoscaler to bring up pod) in the diagrams from y'alls other post?
It was in step #1. Most knative tutorials we found have you set up istio, which was the one setting the headers. There was separate work to rip out istio (which did not scale well either) that we didn't include in the post.
So istio used to sit between our proxy and knative's proxy. In order to figure out what headers it was setting, we ran a caddy container as a sidecar to the activator, and had it output the request metadata. We then read the code to confirm