Concept / Term · Established
Progressive deployment strategies
Canary sends a small share of users to a new version first; blue-green keeps old and new environments live so traffic can switch or roll back safely.
Field note
A canary deployment exposes a new version to a small share of traffic before expanding it. Blue-green keeps old and new production environments ready so traffic can switch between them.
“Canary” borrows from the warning canaries once used in mines. “Blue-green” gives neutral colour names to two equivalent environments so neither is permanently treated as the new one.
Teams watch real-user error and performance signals during the rollout, then continue, pause or return traffic to the known-good version.
Progressive exposure limits the number of users affected when a defect appears only under genuine production conditions.
In a sentence“The canary is healthy at ten per cent, so we can raise it to fifty.”