I need to check whether my EC2 instances are running properly. I have written a script that will help me obtain the instance’s ID and then send a notification to an SNS topic. How can I obtain the instance’s ID?

Answer options:

A.By querying the instance’s Meta Data
B.By querying the instances User Data
C.I need to get authorized with an IAM role prior to accessing the instance’s ID using Metadata
D.I cannot use a script. I need to login to the AWS console & manually check the instance’s ID & its status

Correct Answer: A
Option A is CORRECT. An instance’s Meta data provides me with information about the instance like Instance ID, Local IP, Instance Type etc..I can query the instances Meta data using an internal IP http://169.254.169.254/latest/meta-data/ which can be accessed only from within an EC2 instance
Option B is incorrect. User Data is a section used for providing startup configuration to an EC2 instance. Eg if I need to have an Apache web server running on an EC2 instance after it is provisioned, I can use the User Data section & provide scripts for installing the software during instance creation
Option C is incorrect. Meta data information is available to EC2 instances by default without the need to provide an IAM role for accessing it
Option D is incorrect. Console login or manual intervention is not required to achieve this task. I can write a script & configure it to run at a scheduled time of the day wherein the EC2 instance can express itself to provide its health status.
References:
https://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/instancedata-data-retrieval.html
https://youtu.be/tPQsI8n6er0