Amazon ElastiCache for Redis
ElastiCache for Redis User Guide (API Version 2015-02-02)

Creating a Cache Subnet Group

A cache subnet group is a collection of subnets that you may want to designate for your cache clusters in an Amazon VPC. When launching a cache cluster in an Amazon VPC, you need to select a cache subnet group. Then ElastiCache uses that cache subnet group to assign IP addresses within that subnet to each cache node in the cluster.

For guidance on how to create a subnet group using the ElastiCache Management Console, the AWS CLI, or the ElastiCache API, see Creating a Subnet Group.

After you create a cache subnet group, you can launch a cache cluster to run in your Amazon VPC. Continue to the next topic Creating a Cache Cluster in an Amazon VPC.