You are currently using Elastic Beanstalk to host your production environment. You need to roll out updates to your application hosted on this environment. This is a critical application which is why there is a requirement that the rollback, if required, should be carried out with the least amount of downtime. Which of the following deployment strategies would ideally help achieve this purpose?

Answer options:

A.Create a Cloudformation template with the same resources as those in the Elastic beanstalk environment. If the deployment fails, deploy the Cloudformation template.
B.Use Rolling updates in Elastic Beanstalk so that the rolling updates feature would roll back to the last deployment if the deployment fails.
C.Create another parallel environment in the elastic Beanstalk. Use the Swap URL feature.
D.Create another parallel environment in the elastic Beanstalk. Create a new Route53 Domain name for the new environment and release that URL to the users.

Answer – C
Since the requirement is to have the least amount of downtime, the ideal way is to create a blue-green deployment environment and then use the Swap URL feature to swap environments for the new deployment and then do the swap back, in case the deployment fails.
The AWS Documentation mentions the following on the SWAP URL feature of Elastic Beanstalk.
Because Elastic Beanstalk performs an in-place update when you update your application versions, your application may become unavailable to users for a short period of time. It is possible to avoid this downtime by performing a blue/green deployment, where you deploy the new version to a separate environment and then swap CNAMEs of the two environments to redirect traffic to the new version instantly.