A company is building a new workload on AWS that uses an Application Load Balancer (ALB) The company has configured a new ALB target group that uses…

Slow start mode is designed to gradually increase the traffic sent to a newly registered target, allowing it to "warm up." However, a key prerequisite for this feature to activate is the pre-existence of at least one healthy target in the target group. If a target is registered into an empty target group, or a group where all existing targets are unhealthy, slow start mode will not be initiated for that new target. Once it passes its initial health checks, it will immediately start receiving its full share of traffic, as there are no other healthy targets to handle the load.

A. The round robin routing algorithm is a standard traffic distribution method for ALBs and does not conflict with or prevent the use of slow start mode.

C. An ALB target group can contain a heterogeneous mix of EC2 instance types. There is no requirement for instance type uniformity for slow start to function.

D. The 5-tuple hash is a flow distribution mechanism primarily associated with Network Load Balancers, not Application Load Balancers. It is irrelevant to the ALB's slow start feature.

1. AWS Documentation: Elastic Load Balancing User Guide for Application Load Balancers.

Section: Slow start mode

Content: "Slow start mode can begin only if there is at least one healthy target in the target group. If you enable slow start on a target group with no healthy targets, the new targets do not enter slow start mode when they are registered and pass their initial health checks. As soon as a target group has one healthy target, any subsequent targets registered with the target group enter slow start mode." This directly supports the correct answer (B).

2. AWS Documentation: Elastic Load Balancing User Guide for Application Load Balancers.

Section: Routing algorithm

Content: "With the round robin routing algorithm, the load balancer node that receives the request selects a target from the target group for the active rule, and sends the request to the selected target." This describes the default behavior and makes no mention of it conflicting with slow start, invalidating option (A).