GitHub's outage: your autoscaling policy is blind to the sidecar it scales
The GitHub outage traces partly to an autoscaling policy that watched the host service's load but never the Istio sidecar's concurrency limits, so the sidecar saturated and couldn't spin up. One system's saturation can hide while another metric looks healthy, as Slack proved back in 2021. Autoscaling is bespoke operational engineering per service, not a check-the-box feature, and it only surfaces under load testing everyone should be doing.