AWS CloudFormation
User Guide (API Version 2010-05-15)

Amazon ElastiCache ReplicationGroup NodeGroupConfiguration

NodeGroupConfiguration is a property of the AWS::ElastiCache::ReplicationGroup resource that configures an Amazon ElastiCache (ElastiCache) Redis cluster node group.


To declare this entity in your AWS CloudFormation template, use the following syntax:


{ "NodeGroupId" : String, "PrimaryAvailabilityZone" : String, "ReplicaAvailabilityZones" : [ String, ... ], "ReplicaCount" : Integer, "Slots" : String }


NodeGroupId: String PrimaryAvailabilityZone: String ReplicaAvailabilityZones: - String ReplicaCount: Integer Slots: String



Either the ElastiCache for Redis supplied 4-digit id or a user supplied id for the node group these configuration values apply to.

Length Constraints: Minimum length of 1. Maximum length of 4.

Pattern: \d+

Required: No

Type: String

Update requires: Some interruptions. Update requires no interruption if the resource contains an UseOnlineResharding update policy set to true. Update requires replacement if the resource does not contain an UseOnlineResharding update policy, or the policy is set to false. For more information, see UseOnlineResharding Policy.


The Availability Zone where ElastiCache launches the node group's primary node.

Required: No

Type: String

Update requires: Replacement


A list of Availability Zones where ElastiCache launches the read replicas. The number of Availability Zones must match the value of the ReplicaCount property or, if you don't specify the ReplicaCount property, the replication group's ReplicasPerNodeGroup property.

Required: No

Type: List of String values

Update requires: Replacement


The number of read replica nodes in the node group.

Required: No

Type: Integer

Update requires: Replacement


A string of comma-separated values where the first set of values are the slot numbers (zero based), and the second set of values are the keyspaces for each slot. The following example specifies three slots (numbered 0, 1, and 2): 0,1,2,0-4999,5000-9999,10000-16,383.

If you don't specify a value, ElastiCache allocates keys equally among each slot.

When you use an UseOnlineResharding update policy to update the number of node groups without interruption, ElastiCache evenly distributes the keyspaces between the specified number of slots. This cannot be updated later. Therefore, after updating the number of node groups in this way, you should remove the value specified for the Slots property of each NodeGroupConfiguration from the stack template, as it no longer reflects the actual values in each node group. For more information, see UseOnlineResharding Policy.

Required: No

Type: String

Update requires: Replacement

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