How can the developer achieve this with MINIMAL impact on users?
Change the application to use an alias that points to the current version. Deploy the new version of the code. Update the alias to use the newly deployed version. If too many errors are encountered, point the alias back to the previous version.
Change the application to use an alias that points to the current version. Deploy the new version of the code. Update the alias to direct 10% of users to the newly deployed version. If too many errors are encountered, send 100% of traffic to the previous version.
Do not make any changes to the application. Deploy the new version of the code. If too many errors are encountered, point the application back to the previous version using the version number in the Amazon Resource Name (ARN).
Create three aliases: new, existing, and router. Point the existing alias to the current version. Have the router alias direct 100% of users to the existing alias. Update the application to use the router alias. Deploy the new version of the code. Point the new alias to this version. Update the router alias to direct 10% of users to the new alias. If too many errors are encountered, send 100% of traffic to the existing alias.
Explanations:
While this option allows rolling back by updating the alias, it does not ensure gradual traffic shifting. The rollback is more abrupt compared to controlled traffic shifting.
This option uses gradual traffic shifting with an alias, allowing 10% of users to access the new version. It provides a controlled rollback if errors occur.
This option does not leverage aliases for gradual traffic shifting, and switching back to a previous version using ARN does not minimize impact or provide controlled rollback.
While this option introduces multiple aliases and controlled traffic shifting, it adds unnecessary complexity with multiple aliases, making it less minimal than option B.
I design that the answer is:
Change the application to use an alias that points to the current version. Deploy the new version of the code. Update the alias to direct 10% of users to the newly deployed version. If too many errors are encountered, send 100% of traffic to the previous version.