saving php session in elasticache

I am trying to save php session in elasticache (2 nodes), but failing. I have 2 servers both show different session values, instead of being same.
Here are the 2 ways i tried connecting to elasticache:

session.save_handler = memcached
session.save_path = "tcp://XXXX.euw1.cache.amazonaws.com:11211"

and at node level

session.save_handler = memcached
session.save_path = "tcp://XXXX.0001.euw1.cache.amazonaws.com:11211, tcp://XXXX.0002.euw1.cache.amazonaws.com:11211"

I also installed the elasticache client, adding value to /etc/php.d/memcached.ini

extension=amazon-elasticache-cluster-client.so

I can see individual server holding to their session values but not across the servers.
What am I missing?