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

Creating a Subnet Group

When you create a new subnet group, note the number of available IP addresses. If the subnet has very few free IP addresses, you might be constrained as to how many more nodes you can add to the cluster. To resolve this issue, you can assign one or more subnets to a subnet group so that you have a sufficient number of IP addresses in your cluster's Availability Zone. After that, you can add more nodes to your cluster.

The following procedures show you how to create a subnet group called mysubnetgroup (console), the AWS CLI, and the ElastiCache API.

Creating a Subnet Group (Console)

The following procedure shows how to create a subnet group (console).

To create a subnet group (Console)

  1. Sign in to the AWS Management Console, and open the ElastiCache console at

  2. In the navigation list, choose Subnet Groups.

  3. Choose Create Subnet Group.

  4. In the Create Subnet Group wizard, do the following. When all the settings are as you want them, choose Yes, Create.

    1. In the Name box, type a name for your subnet group.

    2. In the Description box, type a description for your subnet group.

    3. In the VPC ID box, choose the Amazon VPC that you created.

    4. In the Availability Zone and Subnet ID lists, choose the Availability Zone and ID of your private subnet, and then choose Add.

									Image: Create Subnet VPC screen
  5. In the confirmation message that appears, choose Close.

Your new subnet group appears in the Subnet Groups list of the ElastiCache console. At the bottom of the window you can choose the subnet group to see details, such as all of the subnets associated with this group.

Creating a Subnet Group (AWS CLI)

At a command prompt, use the command create-cache-subnet-group to create a subnet group.

For Linux, macOS, or Unix:

aws elasticache create-cache-subnet-group \ --cache-subnet-group-name mysubnetgroup \ --cache-subnet-group-description "Testing" \ --subnet-ids subnet-53df9c3a

For Windows:

aws elasticache create-cache-subnet-group ^ --cache-subnet-group-name mysubnetgroup ^ --cache-subnet-group-description "Testing" ^ --subnet-ids subnet-53df9c3a

This command should produce output similar to the following:

{ "CacheSubnetGroup": { "VpcId": "vpc-37c3cd17", "CacheSubnetGroupDescription": "Testing", "Subnets": [ { "SubnetIdentifier": "subnet-53df9c3a", "SubnetAvailabilityZone": { "Name": "us-west-2a" } } ], "CacheSubnetGroupName": "mysubnetgroup" } }

For more information, see the AWS CLI topic create-cache-subnet-group.

Creating a Subnet Group (ElastiCache API)

Using the ElastiCache API, call CreateCacheSubnetGroup with the following parameters:

  • CacheSubnetGroupName=mysubnetgroup

  • CacheSubnetGroupDescription==Testing

  • SubnetIds.member.1=subnet-53df9c3a

Example ?Action=CreateCacheSubnetGroup &CacheSubnetGroupDescription=Testing &CacheSubnetGroupName=mysubnetgroup &SignatureMethod=HmacSHA256 &SignatureVersion=4 &SubnetIds.member.1=subnet-53df9c3a &Timestamp=20141201T220302Z &Version=2014-12-01 &X-Amz-Algorithm=AWS4-HMAC-SHA256 &X-Amz-Credential=<credential> &X-Amz-Date=20141201T220302Z &X-Amz-Expires=20141201T220302Z &X-Amz-Signature=<signature> &X-Amz-SignedHeaders=Host