ELB does auto-scaling of resources?

[Mahnoor Malik]

This is related to “AWS Certified Cloud Practitioner Practice Exams 2021“. In the question “What is the primary reason why you should be using an elastic load balancer?”,

“ELBs provide elasticity by directing traffic to a minimum number of instances required to handle the traffic load” is marked as the right answer. The answer suggests that ELB auto-scales the instances/resources, which is not true. ELB can only scale its request handling capacity in response to incoming application traffic.

• This discussion was modified 2 years, 9 months ago by  Mahnoor Malik.

[adrianformaran_tutorialsdojo]

Hi Mahnoor,

Thank you for submitting your question. I’ll do my best to clarify this item for you.

In this item’s explanation, we only mentioned that the ELBs are directing traffic (or routing traffic in other terms) to a minimum number of instances, which is the primary purpose of using an ELB -> elasticity.

We did not mention in the explanation that the ELB was scaling the backend instances.

Please see the first paragraph of this reference for AWS Elastic Load Balancer for further information: https://docs.aws.amazon.com/elasticloadbalancing/latest/userguide/how-elastic-load-balancing-works.html

Regards,

Adrian Formaran @ Tutorials Dojo

[Mahnoor Malik]

We can configure the weights for each target group, which determines the portion of the incoming traffic for each target group.

I can not find in any documentation that “ELB directs traffic to a minimum number of instances”. Although it doesn’t direct traffic to unhealthy instances, but it distributes the traffic evenly across the healthy targets based on the weights we assign to these target groups.

[adrianformaran_tutorialsdojo]

Hi Mahnoor,

You are correct in the scenario that you have multiple target groups attached to your ELB, but for this item we have, we are only discussing one target group attached to the ELB but the target group has multiple targets joined to it, which is the common scenario for CCP. I believe the confusion is because of the phrase minimum number of instances, so we’ll rephrase this section to deliver our intended meaning better.

Regards,

Adrian Formaran @ Tutorials Dojo