AWS SA Professional – Practice Question 9

question

When deploying a highly available 2-tier web application on AWS, which combination of AWS Services meets the requirements? (Choose 1)

  1. AWS Direct Connect
  2. Amazon Route53
  3. AWS Storage Gateway
  4. Elastic Load Balancing
  5. Amazon EC2
  6. Auto Scaling
  7. Amazon VPC
  8. AWS CloudTrail

a. 1, 2, 5 and 6

b. 3, 4, 5 and 8

c. 1, 3, 5 and 7

d. 1 through 8

e. 2, 4, 5 and 6

This question is testing your overall knowledge of a number of fundamental AWS Services that are the basic building blocks to pretty much all deployments.

In my opinion if you’re studying for the AWS Solution Architect Professional you should already know what each of these Services does and what it’s use case is for.

AWS Direct Connect

AWS Direct Connect makes it easy to establish a dedicated network connection from your premises to AWS. Using AWS Direct Connect, you can establish private connectivity between AWS and your datacenter, office, or colocation environment, which in many cases can reduce your network costs, increase bandwidth throughput, and provide a more consistent network experience than Internet-based connections.

Amazon Route 53

Amazon Route 53 is a highly available and scalable cloud Domain Name System (DNS) web service. It is designed to give developers and businesses an extremely reliable and cost effective way to route end users to Internet applications by translating names like http://www.example.com into the numeric IP addresses like 192.0.2.1 that computers use to connect to each other.

AWS Storage Gateway

AWS Storage Gateway is a hybrid storage service that enables your on-premises applications to seamlessly use storage in the AWS Cloud. You can use the service for backup and archiving, disaster recovery, cloud bursting, storage tiering, and migration.

Elastic Load Balancing

Elastic Load Balancing automatically distributes incoming application traffic across multiple Amazon EC2 instances. It enables you to achieve fault tolerance in your applications, seamlessly providing the required amount of load balancing capacity needed to route application traffic.

Amazon EC2

Amazon Elastic Compute Cloud (Amazon EC2) is a web service that provides secure, resizable compute capacity in the cloud. It is designed to make web-scale cloud computing easier for developers.

Auto Scaling

Auto Scaling helps you maintain application availability and allows you to dynamically scale your Amazon EC2 capacity up or down automatically according to conditions you define.

Amazon VPC

Amazon Virtual Private Cloud (Amazon VPC) lets you provision a logically isolated section of the Amazon Web Services (AWS) cloud where you can launch AWS resources in a virtual network that you define.

AWS CloudTrail

AWS CloudTrail is a service that enables governance, compliance, operational auditing, and risk auditing of your AWS account. With CloudTrail, you can log, continuously monitor, and retain account activity related to actions across your AWS infrastructure. CloudTrail provides event history of your AWS account activity, including actions taken through the AWS Management Console, AWS SDKs, command line tools, and other AWS services.

“Answer A” is incorrect.  This is recommending to use Direct Connect as part of the Solution to deliver high availability.  Direct Connect is not inherently resilient and therefore you would need to provision multiple Direct Connects to ensure resilience.  Similarly this isn’t recommending to use an Elastic Load Balancer, however this isn’t necessary assuming that the EC2 instances are configured with Elastic IP’s and then registered as a DNS Record within Route 53.

“Answer B” is also incorrect.  This has suggested using an AWS Storage Gateway which is also not able to deliver high availability.  Storage Gateway isn’t providing any benefit given that the question is implying that you’re building it new on AWS and Storage Gateway is fundamentally utilised to assist with on-premises servers having access to cloud storage.  In addition whilst the web server would be behind an Elastic Load Balancer making it highly available you wouldn’t be able to access the site using a friendly name such as http://www.example.com unless you were hosting your DNS zone somewhere else such as GoDaddy.  Finally given that you’re not making use of Auto Scaling the EC2 instance have no ability to scale out when the demand hits a significant level and potentially may not be able to respond to the requests.

“Answer C” is incorrect.  As mentioned in why “Answer A” and “Answer B” were incorrect, this is recommending the use of both Direct Connect and AWS Storage Gateway.  Specifically this isn’t making use of either Route 53 or Elastic Load Balancing meaning the EC2 instances would need to be using Elastic IPs and would be accessed individually without the use of any Auto Scaling either.

“Answer D” whilst it’s recommending to utilise everything and would achieve the desired outcome this wouldn’t be cost effective as it could be done in a more economical way.  There are some services that potentially aren’t required e.g. Direct Connect & Storage Gateway.

“Answer E” is the correct answer.  It’s recommending to use all the key features that would make a two-tier web site highly available.  You’d be using Route 53 for hosting the DNS, this in turn would have a DNS record that would point to the Elastic Load Balancer that is inherently highly available.  The ELB would load balance the web traffic over some EC2 instances that would be configured to auto-scale to horizontally scale out when the instances hit certain thresholds (that you would configure) and scale back when those conditions have subsided.

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