Blue-Green deployment is a method of installing changes to a web, app, or database server by swapping alternating production and staging servers.
In this method, two identical production environments work in parallel.
One is the currently-running production environment receiving all user traffic (depicted as Blue). The other is a clone of it, but idle (Green). Both use the same database back-end and app configuration.
The new version of the application is deployed in the green environment and tested for functionality and performance. Once the testing results are successful, application traffic is routed from blue to green. Green then becomes the new production.
If there is an issue after green becomes live, traffic can be routed back to blue.
A more risk-averse strategy is Canary Deployment, which is like Blue-Green Deployment, but Instead of switching from blue to green in one step, you use a phased approach.
Other Deployment Strategies
- Big bang Deployment
- Rolling Deployment
- Canary Deployment
References
https://en.wikipedia.org/wiki/Blue-green_deployment
https://dev.to/mostlyjason/intro-to-deployment-strategies-blue-green-canary-and-more-3a3
