A banking web application is using Elastic load Balancer in front of web servers deployed across AZ in us-west-1 region. The banking application has its own session cookie. The development team wants user sessions to bind to specific instances within an AZ. Which of the following CLI command can be used to meet this requirement?

Answer options:

A.aws elb create-lb-cookie-stickiness-policy --load-balancer-name us-west1-load-balancer --policy-name elb-cookie-policy --cookie-expiration-period 60
B.aws elb create-app-cookie-stickiness-policy --load-balancer-name us-west1-load-balancer --policy-name elb-cookie-policy --cookie-name bank-app-cookie
C.aws elb create-lb-cookie-stickiness-policy --load-balancer-name us-west1-load-balancer --policy-name elb-cookie-policy -- cookie-name bank-app-cookie
D.aws elb create-app-cookie-stickiness-policy --load-balancer-name us-west1-load-balancer --policy-name elb-cookie-policy -- cookie-expiration-period 90

Correct Answer: B
Classic Load Balancer or Elastic Load Balancer can be configured to follow the application session cookie or session cookie generated with stickiness duration. This will make the user session bind to a specific instance. In the above case, ELB needs to be configured to follow the banking application session cookie. For this, you need to specify the load balancer name, policy name & cookie name.
Option A & C are incorrect as this will create a session cookie on ELB based upon time duration.
Option D is incorrect as when ELB is configured to follow the application session cookie, duration is not required to be specified. It will follow the duration as specified in the application session cookie.
For more information on ELB CLI, refer to the following URLs-
https://docs.aws.amazon.com/cli/latest/reference/elb/create-app-cookie-stickiness-policy.html