Answers: C and D
Option A is incorrect because the first level of redundancy is always Availability Zones when it comes to High Availability & Performance. When applications are deployed across multiple Availability Zones within the same region, a single Availability Zone`s failure will not result in the application being unavailable as the failover mechanism will switch the request of a client to another availability zone. When requests are routed through a load-balancer, it will manage requests depending on the resource utilization of services within an availability zone. This will ensure the good performance of the application. Regional replications are a second level of redundancy where data is replicated between Geographical Regions. One of the reasons could be a Disaster Planning architecture for Business Continuity where a complete Region becomes unavailable & a backup of the data can be maintained in another region for redundancy.
Option B is incorrect. Edge locations are used by services like CloudFront to cache data & reduce latency for end-user access by using those Edge locations as a Global Content Delivery Network (CDN). EC2 instances can be used as Origin servers to a CloudFront distribution for serving dynamic content.
Option C is CORRECT. An Availability Zone is a logical Data Center within a Region. Each zone in a Region has redundant and separate power, networking and connectivity to reduce the likelihood of two zones failing simultaneously. Each zone could be backed with one or more physical Data Centers, the largest being backed by 5.
Option D is CORRECT. Copying an AMI from one region to another enables you to launch consistent instances based on the same AMI to different Regions. The consistency can be observed from the fact that the AMI’s can contain pre-installed software that can be used in different regions. For example, if I have a redundant AMI copy as a backup in another Region, it becomes easy to launch an EC2 instance from that AMI in that Region without re-installing all those software again, thus improving downtime of my applications.
Option E is incorrect. Elastic IP (EIP) addresses are static IP addresses that can be created and assigned within an AWS Account rather than an Availability Zone. You can have a maximum of 5 EIP’s for an Account. It can be assigned to an EC2 instance. An EIP is most useful for an application hosted on a single EC2 instance with its IP mapped to a domain name. When the EC2 instance has a public IP & getting restarted, it will be assigned a new public IP making the site unavailable unless it is remapped to the domain. An EIP will help here by retaining the same public IP address at the time of a server restart so that the site does not incur downtime.
Diagrams:
References:
https://aws.amazon.com/about-aws/global-infrastructure/?p=ngi&loc=0
https://digitalcloud.training/certification-training/aws-certified-cloud-practitioner/aws-global-infrastructure/
https://aws.amazon.com/blogs/aws/ec2-ami-copy-between-regions/
https://www.rackspace.com/blog/aws-101-regions-availability-zones#:~:text=An%20availability%20zone%20is%20a,use%20by%20any%20AWS%20customer.&text=In%20each%20zone%2C%20participating%20data,over%20redundant%20private%20network%20links.