A developer wants to use an environment that has two sets of servers, with one active and one passive at any time. When a new version of the application is ready, it will be installed to the passive s

Disaster recovery environments are standby replicas designed to take over during a failure event, not for routine application deployment workflows.

In a blue-green deployment strategy, two parallel server sets are maintained - one actively serving traffic and one passive. When a new release is ready it is deployed to the passive set, which is then promoted to active by redirecting traffic, allowing instant rollback by reverting the switch. This matches exactly the described scenario of active and passive server sets that swap roles on each release.

A development environment is where code is written and unit-tested by developers, not a production-mirrored passive server set used for release promotion.

A staging environment is a single pre-production environment used for final testing before release, not a paired active-passive setup that swaps on deployment.