You need to design a VPC for a web-application consisting of an Elastic Load Balancer (ELB). a
fleet of web/application servers, and an RDS database The entire Infrastructure must be
distributed over 2 availability zones.
Which VPC configuration works while assuring the database is not available from the Internet?
A.
One public subnet for ELB one public subnet for the web-servers, and one private subnet for
the database
B.
One public subnet for ELB two private subnets for the web-servers, two private subnets for
RDS
C.
Two public subnets for ELB two private subnets for the web-servers and two private subnets for
RDS
D.
Two public subnets for ELB two public subnets for the web-servers, and two public subnets for
RDS
The entire infrastructure must be distributed with 2 AZs so correct answer should be C.
c
c
Ans: B (One public subnet for ELB two private subnets for the web-servers, two private subnets for RDS)
yes C as B state on one Public sub net for the ELB and if we will do that the ELB will drop an error that it needs at least 2 sub net on private for the HA
The answer is C. Here is why you should have two public subnets when you have launched instances in private subnets.
A – It is wrong because this doesn’t provide any High availability
B – It is correct but you need to provision one more public subnet such the instances in the private subnet are running smoothly
C- The below description says why this option is correct
“When you create a load balancer, you must attach one or more public subnets to the load balancer. If your instances are in private subnets, create public subnets in the same Availability Zones as the subnets with your instances; you will attach these public subnets to the load balancer.”
D – Wrong because RDS has to be launched in the private subnets not in public subnets.
Source: http://docs.aws.amazon.com/ElasticLoadBalancing/latest/DeveloperGuide/setting-up-elb.html
It’s Right “C”