A company is releasing a new version of its web application. The SysOps administrator want… — AWS Certified SysOps Administrator - Associate

A company is releasing a new version of its web application. The SysOps administrator wants to perform a canary deployment by routing $90\%$ of user traffic to the current production Application Load Balancer (ALB) and $10\%$ of traffic to a new ALB. Which Route 53 configuration should the administrator implement to meet these requirements?

Create two Alias A records for the subdomain, both configured with the Weighted routing policy, assigning a weight of $90$ to the production ALB record and $10$ to the new ALB record.Answer
B
Create two CNAME records for the subdomain using the Simple routing policy, with one record pointing to each ALB.
C
Create two Alias A records for the subdomain, both configured with the Failover routing policy, designating the production ALB as primary and the new ALB as secondary.
D
Create a single CNAME record for the subdomain, and use weighted records within the ALB target groups to split the DNS traffic.

Answer

Create two Alias A records for the subdomain, both configured with the Weighted routing policy, assigning a weight of

90

to the production ALB record and

10

to the new ALB record.

The correct configuration uses the Weighted routing policy with two Alias A records. This allows the administrator to split DNS traffic in a

90:10

proportion (by setting weights of

90

and

10

). Using Alias records rather than CNAMEs is the recommended AWS best practice for mapping domains to load balancers, as they automatically update when the ALB IPs change and do not incur query charges.

Step-by-Step Solution

Determine the routing policy required to split traffic based on percentages (

90\%

and

10\%

The Weighted routing policy is selected because it enables routing traffic to multiple resources in user-specified proportions.

Other routing policies like Simple or Failover do not support percentage-based distribution.

Select the appropriate record type for the Application Load Balancers.

Alias A records are chosen because they map directly to AWS resources (like ALBs) and are automatically updated when the ALB's underlying IP addresses change.

CNAME records incur standard Route 53 query charges and cannot be used at the zone apex.

Configure the weights for the two records.

Assign a weight of

90

to the record pointing to the production ALB and a weight of

10

to the record pointing to the new ALB.

This mathematically splits the traffic at a

9:1

ratio, corresponding to the required

90\%

and

10\%

distribution.

Key Concept

Weighted routing policy and Alias records in Route 53

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

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