ASG – AMI – user data – X-Ray daemon

[kung]

Scenario:

“The application will be hosted in an Auto Scaling group of Linux EC2 instances and it must be instrumented so it can send the trace data to the AWS X-Ray service.

Which of the following options is the MOST suitable way to satisfy this requirement?”

“Include the xray-daemon.config configuration file in the AMI.” versus “Use a user data script to install the X-Ray daemon.” answer.

Agreed with the reasoning that the “xray-daemon.config configuration file” is for Elastic Beanstalk, not X-Ray, but does that invalidate the core of the answer ‘in the AMI’? (as it also doesn’t hurt to have a configuration file in the AMI that doesn’t matter)

If you have an Auto Scaling Group, you want to be able to quickly scale out with new EC2 Instances if required. You do NOT want to have to install all kind of software during boot (i.e. in the user data script), but instead have an AMI with everything in it ready to roll (best practice).

Just my 2 cents.

Cheers,
Robert

[Jon-Bonso]

Hi Robert,

You have a valid point about integrating the X-Ray into the AMI. However, there are also some situations where you want to loosely couple your AMI and your custom configuration (via user data). Nevertheless, I agree that using an AMI with the X-ray configuration is valid, given that it doesn’t use the “xray-daemon.config” which is only meant for Elastic Beanstalk.

For Auto Scaling, you can specify user data to configure an EC2 instance or run a configuration script during launch. If you launch more than one instance at a time, the user data is available to all the instances in that reservation.

Let us know if you need further assistance. The Tutorials Dojo team is dedicated to help you pass your AWS exam on your first try!

Regards,

Jon Bonso @ Tutorials Dojo