A blue–green deployment installs a release on a second, idle set of hosts (green) while the current set (blue) serves, then switches traffic to green at once; switching back is the rollback, the return to the previous release, which a blue–green deployment makes a switch rather than a reinstallation.
Quantitative Finance · Glossary
What is Blue–green deployment, rollback?
Also known as: blue--green deployment · rollback