Exam ANS-C00 topic 1 question 73 discussion

I'll go for D. User-Agent is a HTTP Header which Contains a characteristic string that allows the network protocol peers to identify the application type, operating system, software vendor or software version of the requesting software user agent. ALB has the capability to route based on headers, no other ELB has that capability. C could be true but they dont mention if the new and old apps have different URLs so D is the likely answer IMO

I think C is more practical. Send traffic to www.www.example.com, route 53 sends the traffic to the ALB. If path /v1 send to different target group. If path is /v2 send to different target group. V1 target group send traffic to on-prem, v2 sends traffic to new version in vpc

D sounds like a proper solution to what is given in the scenario.

A is completely out. It doesn't help to return multiple IP addresses. Client wouldn't know which one to us. B does require backend to redirect traffic which doesn't make sense. Request should never reach backend that's not addressed to it. D is only viable if we use different domain names for the application, which we don't. C is the only viable since I can point to the specific version using path.

A Classic Load Balancer is rarely used in today's environments

C option mentioned applications behind load balancer while D mention application backend behind loadbalance. seems like C is the answer

C and D both are close. But I will go for D. There are two application versions. Question does not state that they are access using different URLs (hosts). Why would you publish new URL for new version. e.g. v1.abc.com for version1 and v2.abc.com for version2. It makes things complex. It is just different Path in the URL. Like (abc.com/v1 or abc.com/v2) Therefore choosing D is correct.

It's about ALB listener condition rule with D we need 2 cname records which are not mentioned -> I will go with C

The host header specifies which website or web application should process an incoming HTTP request. So ANS is D

It is indeed very close tie between C and D, however based on the information on the link below, I am going for D. https://aws.amazon.com/about-aws/whats-new/2019/03/application-load-balancers-now-support-advanced-request-routing/

C or D. It is impossible to answer this question because it depends of an arbitrary choice of the developers how they differentiate old and new apps. I lean to C because D will require new DNS entry, not mentioned in D.

I will go to C. I would imagine for the new or old version would appear on the path, instead of using different domain name? Not sure

I have questions about C or D, in this questions, there mentioned about 'earlier client version' which means can't be supported layer7 (Application load balancer). How it could be answers for this questions?

Pretty sure it's D...The app may not use a different path (so C is out), but most likely something in the header to determine the version.

Req is to update their client application too - so C. D switches only to appropriate backend but client remains.

Answer is D. “ Application Load Balancers now support request routing based on standard or custom HTTP headers and methods, query parameters, and source IP addresses. This launch extends the existing support for Host header and path-based routing rules in Application Load Balancers to more fields from HTTP request messages. This richer set of routing criteria enables you to further simplify your application architecture by offloading routing functionality to the load balancer. It can also be used to block unwanted traffic at the load balancer.” https://aws.amazon.com/about-aws/whats-new/2019/03/application-load-balancers-now-support-advanced-request-routing/

my answer is D