Amazon ElastiCache
API Reference (API Version 2015-02-02)

DecreaseReplicaCount

Dynamically decreases the number of replics in a Redis (cluster mode disabled) replication group or the number of replica nodes in one or more node groups (shards) of a Redis (cluster mode enabled) replication group. This operation is performed with no cluster down time.

Request Parameters

For information about the parameters that are common to all actions, see Common Parameters.

ApplyImmediately

If True, the number of replica nodes is decreased immediately. ApplyImmediately=False is not currently supported.

Type: Boolean

Required: Yes

ReplicationGroupId

The id of the replication group from which you want to remove replica nodes.

Type: String

Required: Yes

NewReplicaCount

The number of read replica nodes you want at the completion of this operation. For Redis (cluster mode disabled) replication groups, this is the number of replica nodes in the replication group. For Redis (cluster mode enabled) replication groups, this is the number of replica nodes in each of the replication group's node groups.

The minimum number of replicas in a shard or replication group is:

  • Redis (cluster mode disabled)

    • If Multi-AZ with Automatic Failover is enabled: 1

    • If Multi-AZ with Automatic Failover is not enabled: 0

  • Redis (cluster mode enabled): 0 (though you will not be able to failover to a replica if your primary node fails)

Type: Integer

Required: No

ReplicaConfiguration.ConfigureShard.N

A list of ConfigureShard objects that can be used to configure each shard in a Redis (cluster mode enabled) replication group. The ConfigureShard has three members: NewReplicaCount, NodeGroupId, and PreferredAvailabilityZones.

Type: Array of ConfigureShard objects

Required: No

ReplicasToRemove.member.N

A list of the node ids to remove from the replication group or node group (shard).

Type: Array of strings

Required: No

Response Elements

The following element is returned by the service.

ReplicationGroup

Contains all of the attributes of a specific Redis replication group.

Type: ReplicationGroup object

Errors

For information about the errors that are common to all actions, see Common Errors.

ClusterQuotaForCustomerExceeded

The request cannot be processed because it would exceed the allowed number of clusters per customer.

HTTP Status Code: 400

InsufficientCacheClusterCapacity

The requested cache node type is not available in the specified Availability Zone. For more information, see InsufficientCacheClusterCapacity in the ElastiCache User Guide.

HTTP Status Code: 400

InvalidCacheClusterState

The requested cluster is not in the available state.

HTTP Status Code: 400

InvalidParameterCombination

Two or more incompatible parameters were specified.

HTTP Status Code: 400

InvalidParameterValue

The value for a parameter is invalid.

HTTP Status Code: 400

InvalidReplicationGroupState

The requested replication group is not in the available state.

HTTP Status Code: 400

InvalidVPCNetworkStateFault

The VPC network is in an invalid state.

HTTP Status Code: 400

NodeGroupsPerReplicationGroupQuotaExceeded

The request cannot be processed because it would exceed the maximum allowed number of node groups (shards) in a single replication group. The default maximum is 15

HTTP Status Code: 400

NodeQuotaForCustomerExceeded

The request cannot be processed because it would exceed the allowed number of cache nodes per customer.

HTTP Status Code: 400

NoOperationFault

The operation was not performed because no changes were required.

HTTP Status Code: 400

ReplicationGroupNotFoundFault

The specified replication group does not exist.

HTTP Status Code: 404

ServiceLinkedRoleNotFoundFault

The specified service linked role (SLR) was not found.

HTTP Status Code: 400

Examples

Example

The following example removes two replicas from each node group in the replication group sample-repl-group.

https://elasticache.us-west-2.amazonaws.com/ ?Action=DecreaseReplicaCount &ApplyImmediately=True &NewReplicaCount=2 &ReplicasToRemove.ReplicaToRemove.1=0001 &ReplicasToRemove.ReplicaToRemove.2=0003 &ReplicationGroupId=sample-repl-group &Version=2015-02-02 &SignatureVersion=4 &SignatureMethod=HmacSHA256 &Timestamp=20150202T192317Z &X-Amz-Credential=<credential>

Example

The following example removes replicas from two node groups. Because there are multiple node groups, this example is for a Redis (cluster mode enabled) replication group.

https://elasticache.us-west-2.amazonaws.com/ ?Action=DecreaseReplicaCount &ApplyImmediately=True &ReplicaConfiguration.ConfigureShard.1.NodeGroupId=0001 &ReplicaConfiguration.ConfigureShard.1.NewReplicaCount=1 &ReplicaConfiguration.ConfigureShard.1.PreferredAvailabilityZones.PreferredAvailabilityZone.1=us-east-1a &ReplicaConfiguration.ConfigureShard.1.PreferredAvailabilityZones.PreferredAvailabilityZone.2=us-east-1c &ReplicaConfiguration.ConfigureShard.2.NodeGroupId=0003 &ReplicaConfiguration.ConfigureShard.2.NewReplicaCount=2 &ReplicaConfiguration.ConfigureShard.2.PreferredAvailabilityZones.PreferredAvailabilityZone.1=us-east-1a &ReplicaConfiguration.ConfigureShard.2.PreferredAvailabilityZones.PreferredAvailabilityZone.2=us-east-1b &ReplicaConfiguration.ConfigureShard.2.PreferredAvailabilityZones.PreferredAvailabilityZone.4=us-east-1c &ReplicationGroupId=samplem--repl-group &Version=2015-02-02 &SignatureVersion=4 &SignatureMethod=HmacSHA256 &Timestamp=20150202T192317Z &X-Amz-Credential=<credential>

See Also

For more information about using this API in one of the language-specific AWS SDKs, see the following: