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Question 32

A network engineer needs to set up an Amazon EC2 Auto Scaling group to run a Linux-based network appliance in a highly available architecture. The network engineer is configuring the new launch template for the Auto Scaling group.

In addition to the primary network interface the network appliance requires a second network interface that will be used exclusively by the application to exchange traffic with hosts over the internet. The company has set up a Bring Your Own IP (BYOIP) pool that includes an Elastic IP address that should be used as the public IP address for the second network interface.

How can the network engineer implement the required architecture?

    Correct Answer: D

    To set up an Amazon EC2 Auto Scaling group that can handle a second network interface meant for public traffic, the user data option can be leveraged. This allows the network engineer to run a cloud-init script during instance initialization. The script can be used to configure the secondary network interface and allocate an Elastic IP address from the BYOIP pool. This approach ensures the secondary interface is properly configured and associated with the correct public IP, satisfying the requirement for high availability and specific network configuration.

Discussion
rhinozD

A is incorrect. EC2 Auto Scaling supports attaching a second elastic network interface automatically when Auto Scaling spins up a new instance. However, both elastic network interfaces attached to the instance are in the same subnet. So you can: 1. Combine Lambda + Lifecycle hook + eventbridge to assign the second elastic network interface 2. or use cloud-init. -> D is correct.

vikasj1inOption: D

During the creation of the Auto Scaling group, you can select the subnets for the primary network interface. Using user data, you can run a cloud-init script to allocate and configure the second network interface during the instance launch process. The cloud-init script can also handle the association of an Elastic IP address from the BYOIP pool to the second network interface. This approach ensures that each instance launched by the Auto Scaling group has the necessary network configuration, including the second network interface with a public IP address from the BYOIP pool.

MBO92

Have you any official documentation that say that is not possible to use launch template in these question uses case?

CertNerd1234

Reason why not option A: it is not possible to choose BYOIP when creating launch template

MBO92

Have you any documentation say this statement that we can not assign BYOIP with launch template? in the launch template we can manually enter the IP while provisioning the different ENIs there is no restriction !

zaazanuna

D - correct.

Tofu13Option: D

RhinozD answer with links https://aws.amazon.com/about-aws/whats-new/2020/11/amazon-ec2-auto-scaling-supports-attaching-multiple-network-interfaces-at-launch/ https://repost.aws/knowledge-center/ec2-auto-scaling-multiple-network-interfaces

MBO92

In the first link you provided said : Previously, customers had to write custom scripts and run lifecycle hooks to attach multiple network interfaces. You can now define multiple network interfaces in a launch template and your Auto Scaling group will automatically attach them to instances as they launch. So answer A is valid. There is no such information in both link said that we cannot use BYOIP inside the Launch template !!

YEBINNNNNOption: D

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DDDDDDDD

Marfee400704

I think that it' correct answer is D accoring to SPOTO products.

marfee

I think that it's correcty answer is D.

i4papaOption: A

A is incorrect

MBO92

Based on which condition you eliminated the answer A?

tycho

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/best-practices-for-configuring-network-interfaces.html

dman

A, not D because ASG with multiple network interfaces, it cannot auto assign Public IPV4 address.

ohcan

I think both A and D are correct, but A is easier and more efficient

ohcan

sorry. I change to D

navi7

why is A incorrect?

slackbot

there does not seem to be a way to select the BYOIP pool in the template

study_aws1

A - correct

study_aws1

Justification for A) - Launch templates can be used to create custom networking configurations. Within a launch template you can add multiple Elastic Network Interfaces (ENIs) and specify settings such as the availability zones they should be connected to. Note that you cannot attach multiple ENIs to an Amazon EC2 instance connected to subnets in different availability zones. Each ENI must be connected to a subnet in the same availability zone.

navi7

is it possible to select BYOIP pool-"id" during creation of launch template? I didn't any. such option.

slackbot

i did not find either. i guess this is why A is incorrect

flowers00

A - correct.

flowers00

Change to D.