New Auto Discovery feature for Amazon ElastiCache: Stakes and Opportunities around the new feature.

For those who unfamiliar, Amazon ElastiCache aims to give you more or less the power to improve application performance by adding a flexible, scalable caching layer between application and your database.

In the past, if you changed the nodes in your cache cluster (for example, by adding a new node); you would have to update the list of node endpoints manually. Typically, updating the list of node endpoints involves reinitializing the client by shutting down and restarting the application, which can result in downtime (depending on how the client application is architected).

Since November 29, 2012, Amazon has released the new Auto Discovery feature which will allow applications to automatically and more or less transparently adapt to the addition or deletion of cache nodes from your cache clusters. Henceforth, the applications can react more quickly to changes in your cache cluster without downtime or manual intervention.

To use Amazon ElastiCache you have to set up a cache cluster (a cache cluster is a collection of cache nodes) and choose the number and the type of nodes to match the performance needs of your application.

All ElastiCache clusters include henceforth a unique Configuration Endpoint, which is a DNS Record that is valid for the lifetime of the cluster. This DNS Record contains the DNS names of each of the nodes that belong to the cluster. You can then connect to the cluster nodes just as before and use the Memcached protocol commands such as get, set, incr, and decr. Finally, to take advantage of Auto Discovery, you will need to use a Memcached client library that is able to use this new feature. Pending a PHP client, a Java client is available and can be downloaded from the ElastiCache Console.