AWS Certified SysOps Administrator – AssociateDeployment, Provisioning, and AutomationMedium
A SysOps Administrator needs to ensure that all Amazon EC2 instances launched in a specific VPC automatically join a corporate Active Directory domain. This process must be fully automated and executed immediately after the instance starts. Which AWS service and feature combination can achieve this reliably?
- AAWS Auto Scaling Group with a custom launch configuration script.
- BAWS Directory Service with a pre-configured domain join script in EC2 User Data.
- CAWS Systems Manager State Manager with an Association targeting new instances.
- DAWS Systems Manager Run Command executed manually after instance launch.
Show answer & explanationAnswer & explanation
Correct answer: B. AWS Directory Service with a pre-configured domain join script in EC2 User Data.
AWS Directory Service provides a feature to automatically join Windows instances to a domain during launch. When combined with EC2 User Data, a script can be executed immediately after the instance starts to perform the domain join, ensuring it happens without manual intervention.
Why the other options are wrong
- A. While Auto Scaling Groups can use launch configurations, a custom script in User Data within the launch configuration is the specific mechanism for domain join, not the ASG itself.
- C. State Manager can enforce configurations, but for an immediate, one-time action right at launch, User Data is more direct and typically used for domain joins with Directory Service.
- D. Run Command is for on-demand execution on running instances; it does not automate actions immediately at launch without further orchestration.
EC2 User Data for Domain Join
EC2 User Data allows scripts to be executed on an EC2 instance during its initial launch, making it ideal for immediate tasks like automatically joining a Windows instance to an Active Directory domain.
- Runs only once at first boot.
- Can be used for bootstrapping and configuration.
- Integrates well with AWS Directory Service for domain joins.
Memory trick: User Data welcomes new EC2 instances to the Directory Service family right away.