In this event, the canary step correctly identified that the new configuration was unsafe. Crucially however, a second software bug in the management software did not propagate the canary step’s conclusion back to the push process, and thus the push system concluded that the new configuration was valid and began its progressive rollout. Classic Two Generals. "No news is good news," generally isn't a good design philo…
anycast "canary test in progress"
edge routers store new configs
anycast "canary test PASS"
edge routers activate new config
edge routers canary test new config (and pass or revert)
edge routers report home that all is well