recently we had switched from aws elb to aws alb; but we are facing issue in aws alb; cookie stickiness is not working at all; for each request (event ajax request on the page) generates a new cookie;
if we switch back to aws elb again cookie stickiness working perfectly fine.
AWSALB is a cookie generated by the Application load balancer in the AWS. It works slightly different from AWSELB.
The ASWALB cookie is load balancer generated cookie. Once the load balancer routes your request to one of the servers, it generates a new cookie and sends it to the client in the response header. Though AWSALB works fine when you just send the webapp_session for consecutive request, it is better to integrate the AWSALB cookie along with the webapp_session and send it for each request to the server. This way, the load balancer will identify your target server and direct your request to the same target in each request call to the server. This preserves the stickyness of the server.
However, if you send AWSALB along with the webapp_session in the request header for each request to the sever, even if the target that processed your previous requests gets busy for future requests, the AWSALB generated in each call will help the load balancer identify your credentials and route your request to the new target. I faced similar situation and this helped me solve the problem.
The "STICKY SESSION" topic in this https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-target-groups.html#sticky-sessions will perhaps help you have some idea.
For Application LB you have to set up session stickiness in target group not directly in LB like in Classic LB. Session stickiness doesn't work when your browser blocks AWSALBCORS, AWSALB - this seems to be obvious, but Internet Explorer can block these cookies and doesn't show any warning/info in console.
