Your manager has assigned you a task to implement a Red/Black deployment strategy for a new project deployed in EC2 instances. You created two similar environments in AWS. Each environment contains an ELB with an Auto Scaling group attached. One environment is used to run the live traffic, and the other one will install the new software release. And the traffic is switched between two environments by updating the DNS records in Route 53. Which description is NOT true for this Red/Black deployment?

Answer options:

A.If issues arise during the deployment, rollback can be easily achieved by modifying Route 53 to shift traffic back to the original environment.
B.Use Amazon Route53 to switch the DNS record to both the "live traffic" environment and the environment that "installs the new software release" simultaneously.
C.Use Amazon Route53 to divert traffic to only one of the environments (i.e) either the "live traffic" or the one that "installs the new software release"at a single point of time.
D.There is no downtime as the old environment can still serve traffic when the new environment is not ready yet.

Correct Answer – B
The Red/Black deployment is a newer term being used by Netflix. About its implementations on AWS, please refer to https://d1.awsstatic.com/whitepapers/AWS_Blue_Green_Deployments.pdf.
Option A is incorrect: Because when issues happen, the deployment can roll back to the original one. This is one major advantage of the Red/Black deployment strategy.
Option B is CORRECT because, for the Red/Black deployment, the DNS switch can happen only to one environment at a time.
Option C is INCORRECT because, with the Red/Black deployment, only one version of the environment ( either Red or Black ) can receive traffic at a time.
Option D is incorrect: Because two similar environments are existing at the same time. When the new environment is being tested, the old environment still serves traffic. This is different from in-place deployment which has a downtime when the upgrade is ongoing.