Blue/Green deployment: a progressive deployment strategy in which both versions get a part of traffic which varies over time, avoiding by cache stampedes on the new release and preserving user experience for the duration of a session in most cases.
It instantiates a new version and then moves traffic to it when its resources are stable.
The blue version (your original version) can be kept up for possible rollback and eventually be decommissioned or used for a subsequent update. There is no downtime associated with blue/green deployments.
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