Your team has maintained a Jenkins server installed in an AWS EC2 instance. The Jenkins server is mainly used to build the artifacts for a Java application. At the moment, there is no disaster recovery strategy for this Jenkins server. Your team needs to design a new disaster recovery plan with both RTO and RPO set as 24 hours. Which disaster recovery strategy should the team choose? 

Answer options:

A.Backup & Restore strategy. For example, backup the Jenkins configuration files every day to an S3 bucket. Use CloudFormation templates to provision the necessary AWS resources.
B.Pilot Light strategy. Use an AMI to launch an EC2 instance in another region and stop the instance to save cost. Start the Pilot Light instance when there is an outage in the original Jenkins server.
C.Warm Standby strategy. Launch a smaller size EC2 instance in the same region but different VPC as a standby.
D.Hot Standby (Multi Site) strategy. Launch a fully operational EC2 instance for the Jenkins server. Suspend its tasks unless a failover happens.

Correct Answer – A
In this case, the EC2 has a Jenkins server installed which is used as a CI/CD server. It is not an application in production, so its impact is quite low. Other than that, as both RPO and RTO are 24 hours, there is plenty of time to recover the server using a backup when there is an outage. The Backup & Restore strategy is enough for this scenario. There are several methods to back the server, such as the Jenkins configuration files, AMI for the EC2 instance, EBS daily snapshots, etc.
About different disaster recovery levels in AWS, refer to https://www.youtube.com/watch?v=lK_t_dhUh5I and https://aws.amazon.com/disaster-recovery/
Option A is CORRECT: Because the Backup & Restore strategy is the most suitable and cost-efficient one considering the given RPO and RTO.
Option B and D are incorrect: Refer to the above explanations.