What is a key characteristic of blue-green deployment?

A key characteristic of blue-green deployment is zero-downtime switching. This deployment strategy involves maintaining two separate environments, known as "blue" and "green." When a new version of an application is ready for deployment, it is fully deployed to the inactive environment (say, green) while the current environment (blue) continues to handle live traffic. Once the new version in the green environment is tested and confirmed to be working properly, traffic is switched from the blue environment to the green environment. This switch is done instantaneously, allowing for no downtime during the release process.

This characteristic not only minimizes disruptions for end-users but also facilitates easy rollback to the previous version (in blue) in case any issues arise after deployment. The ability to perform this switch without downtime is a primary reason why organizations adopt blue-green deployment strategies, as it enhances both the user experience and the overall reliability of application releases.