You are designing Internet connectivity for your VPC. The Web servers must be available on the
Internet. The application must have a highly available architecture.
Which alternatives should you consider? Choose 2 answers
A.
Assign EIPs to all Web servers.
Configure a Route53 record set with all EIPs, with health checks and DNS failover.
B.
Configure a NAT instance in your VPC.
Create a default route via the NAT Instance and associate it with all subnets.
Configure a DNS A record that points to the NAT Instance public IP address.
C.
Configure a CloudFront distribution and configure the origin to point to the private IP addresses of
your Web servers.
Configure a Route53 CNAME record to your CloudFront distribution.
D.
Place all your Web servers behind ELB.
Configure a Route53 CNAME to point to the ELB DNS name.
E.
Configure ELB with an EIP. Place all your Web servers behind ELB.
Configure a Route53 A record that points to the EIP.
A. works as you could script the automatic transfer of the EIPs to new instances if there were issues. Given the current ELB capabilities this solution is a bit out of date for most situations, but it would work.
B. I agree that the NAT does not make sense , yes it is not what a NAT is for and the NAT would become a single point of failure.
C. This does not make any sense to me. CloudFront is a CDN solutions primarily for caching content. It does nothing for high availability. While I need to check this, it sounds like a nonsense to talk about pointing it at the Private IP address of the web servers. Have a read up on CDN and how it is used in the Best Practices white paper.
D. As soon as you see ‘high availability’ think ELB, auto scaling and multi-AZ. This is the primary AWS solution for this problem. I find it interesting that so many people are preoccupied with naked domain name. it wasn’t that many years ago it was considered bad form to direct your root domain name to your primary site. Things change I guess 🙂 . You would just use http://www.DomainName . In reality you would probably use and Alias, but the CNAME will work just as well.
E is a nonsense. You can’t configure EIPs on an ELB, and why would you want to given that they are inherently fault tolerant and are managed by AWS.
So I agree with Answer A & D
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