You are managing a legacy application Inside VPC with hard coded IP addresses in its configuration.
Which two mechanisms will allow the application to failover to new instances without the need for
reconfiguration? (Choose two.)
A.
Create an ELB to reroute traffic to a failover instance
B.
Create a secondary ENI that can be moved to a failover instance
C.
Use Route53 health checks to fail traffic over to a failover instance
D.
Assign a secondary private IP address to the primary ENIO that can be moved to a failover instance
B:D
I think the key parts of the question are
1/ hard coded IP addresses in its (the application) config
2/ failover to new instances without the need for reconfiguration
My reading of point 1 is that the hardcoded IP address in the config must be resolvable on the new instance the application fails over to
My reading of point 2 is that the application must not be reconfigured, i.e. network reconfiguration is fine
On answer D/ I think the answer is referring to moving the secondary private IP assigned to the primary ENI rather than moving the primary ENI itself (this is badly worded and the first time I read this I thought it was referring to the ENI).
Based on neither route 53 nor ELB provide a mechanism to maintain/transition the IP address to a new instance, that rules out A and C, which leaves B and D which will both preserve the IP address on the new failover instance, thus removing the need to reconfigure the application.
16
0