A sys admin is trying to understand the sticky session algorithm. Please select the correct
sequence of steps, both when the cookie is present and when it is not, to help the admin
understand the implementation of the sticky session:
ELB inserts the cookie in the response
ELB chooses the instance based on the load balancing algorithm
Check the cookie in the service request
The cookie is found in the request

The cookie is not found in the request

A.
3,1,4,2 [Cookie is not Present] & 3,1,5,2 [Cookie is Present]

B.
3,4,1,2 [Cookie is not Present] & 3,5,1,2 [Cookie is Present]

C.
3,5,2,1 [Cookie is not Present] & 3,4,2,1 [Cookie is Present]

D.
3,2,5,4 [Cookie is not Present] & 3,2,4,5 [Cookie is Present]

Explanation:
Generally AWS ELB routes each request to a zone with the minimum load. The Elastic Load
Balancer provides a feature called sticky session which binds the user’s session with a specific
EC2 instance. The load balancer uses a special load-balancer-generated cookie to track the
application instance for each request. When the load balancer receives a request, it first checks to
see if this cookie is present in the request. If so, the request is sent to the application instance
specified in the cookie. If there is no cookie, the load balancer chooses an application instance
based on the existing load balancing algorithm. A cookie is inserted into the response for binding
subsequent requests from the same user to that application instance.