You Have an Application Running on Amazon EC2 in an Auto

question 109

Multiple Choice

You have an application running on Amazon EC2 in an Auto Scaling group. Instances are being bootstrapped dynamically, and the bootstrapping takes over 15 minutes to complete. You find that instances are reported by Auto Scaling as being In Service before bootstrapping has completed. You are receiving application alarms related to new instances before they have completed bootstrapping, which is causing confusion. You find the cause: your application monitoring tool is polling the Auto Scaling Service API for instances that are In Service, and creating alarms for new previously unknown instances. Which of the following will ensure that new instances are not added to your application monitoring tool before bootstrapping is completed?

• A) Create an Auto Scaling group lifecycle hook to hold the instance in a pending: wait state until your bootstrapping is complete. Once bootstrapping is complete, notify Auto Scaling to complete the lifecycle hook and move the instance into a pending: complete state.
• B) Use the default Amazon CloudWatch application metrics to monitor your application's health. Configure an Amazon SNS topic to send these CloudWatch alarms to the correct recipients.
• C) Tag all instances on launch to identify that they are in a pending state. Change your application monitoring tool to look for this tag before adding new instances, and the use the Amazon API to set the instance state to 'pending' until bootstrapping is complete.
• D) Increase the desired number of instances in your Auto Scaling group configuration to reduce the time it takes to bootstrap future instances.

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Definitions:

Law of Diminishing

Refers to the principle that as the quantity of a good or input increases, holding all else constant, the added benefit from an additional unit will eventually decline.

Marginal Costs

The increase in total cost that arises from producing one more unit of a product or service.

Stolen Goods

Items that have been taken without permission or acquired through illicit means, with ownership not legally transferred.

Budget Line

A graphical representation of all possible combinations of two goods that can be purchased with a given budget and prices.