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

CreateReplicationGroup

Creates a Redis (cluster mode disabled) or a Redis (cluster mode enabled) replication group.

A Redis (cluster mode disabled) replication group is a collection of clusters, where one of the clusters is a read/write primary and the others are read-only replicas. Writes to the primary are asynchronously propagated to the replicas.

A Redis (cluster mode enabled) replication group is a collection of 1 to 15 node groups (shards). Each node group (shard) has one read/write primary node and up to 5 read-only replica nodes. Writes to the primary are asynchronously propagated to the replicas. Redis (cluster mode enabled) replication groups partition the data across node groups (shards).

When a Redis (cluster mode disabled) replication group has been successfully created, you can add one or more read replicas to it, up to a total of 5 read replicas. You cannot alter a Redis (cluster mode enabled) replication group after it has been created. However, if you need to increase or decrease the number of node groups (console: shards), you can avail yourself of ElastiCache for Redis' enhanced backup and restore. For more information, see Restoring From a Backup with Cluster Resizing in the ElastiCache User Guide.

Note

This operation is valid for Redis only.

Request Parameters

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

ReplicationGroupDescription

A user-created description for the replication group.

Type: String

Required: Yes

ReplicationGroupId

The replication group identifier. This parameter is stored as a lowercase string.

Constraints:

  • A name must contain from 1 to 20 alphanumeric characters or hyphens.

  • The first character must be a letter.

  • A name cannot end with a hyphen or contain two consecutive hyphens.

Type: String

Required: Yes

AtRestEncryptionEnabled

A flag that enables encryption at rest when set to true.

You cannot modify the value of AtRestEncryptionEnabled after the replication group is created. To enable encryption at rest on a replication group you must set AtRestEncryptionEnabled to true when you create the replication group.

Required: Only available when creating a replication group in an Amazon VPC using redis version 3.2.6.

Default: false

Type: Boolean

Required: No

AuthToken

Reserved parameter. The password used to access a password protected server.

AuthToken can be specified only on replication groups where TransitEncryptionEnabled is true.

Important

For HIPAA compliance, you must specify TransitEncryptionEnabled as true, an AuthToken, and a CacheSubnetGroup.

Password constraints:

  • Must be only printable ASCII characters.

  • Must be at least 16 characters and no more than 128 characters in length.

  • Cannot contain any of the following characters: '/', '"', or '@'.

For more information, see AUTH password at http://redis.io/commands/AUTH.

Type: String

Required: No

AutomaticFailoverEnabled

Specifies whether a read-only replica is automatically promoted to read/write primary if the existing primary fails.

If true, Multi-AZ is enabled for this replication group. If false, Multi-AZ is disabled for this replication group.

AutomaticFailoverEnabled must be enabled for Redis (cluster mode enabled) replication groups.

Default: false

Amazon ElastiCache for Redis does not support Multi-AZ with automatic failover on:

  • Redis versions earlier than 2.8.6.

  • Redis (cluster mode disabled): T1 and T2 cache node types.

  • Redis (cluster mode enabled): T1 node types.

Type: Boolean

Required: No

AutoMinorVersionUpgrade

This parameter is currently disabled.

Type: Boolean

Required: No

CacheNodeType

The compute and memory capacity of the nodes in the node group (shard).

The following node types are supported by ElastiCache. Generally speaking, the current generation types provide more memory and computational power at lower cost when compared to their equivalent previous generation counterparts.

  • General purpose:

    • Current generation:

      T2 node types: cache.t2.micro, cache.t2.small, cache.t2.medium

      M3 node types: cache.m3.medium, cache.m3.large, cache.m3.xlarge, cache.m3.2xlarge

      M4 node types: cache.m4.large, cache.m4.xlarge, cache.m4.2xlarge, cache.m4.4xlarge, cache.m4.10xlarge

    • Previous generation: (not recommended)

      T1 node types: cache.t1.micro

      M1 node types: cache.m1.small, cache.m1.medium, cache.m1.large, cache.m1.xlarge

  • Compute optimized:

    • Previous generation: (not recommended)

      C1 node types: cache.c1.xlarge

  • Memory optimized:

    • Current generation:

      R3 node types: cache.r3.large, cache.r3.xlarge, cache.r3.2xlarge, cache.r3.4xlarge, cache.r3.8xlarge

    • Previous generation: (not recommended)

      M2 node types: cache.m2.xlarge, cache.m2.2xlarge, cache.m2.4xlarge

Notes:

  • All T2 instances are created in an Amazon Virtual Private Cloud (Amazon VPC).

  • Redis (cluster mode disabled): Redis backup/restore is not supported on T1 and T2 instances.

  • Redis (cluster mode enabled): Backup/restore is not supported on T1 instances.

  • Redis Append-only files (AOF) functionality is not supported for T1 or T2 instances.

For a complete listing of node types and specifications, see Amazon ElastiCache Product Features and Details and either Cache Node Type-Specific Parameters for Memcached or Cache Node Type-Specific Parameters for Redis.

Type: String

Required: No

CacheParameterGroupName

The name of the parameter group to associate with this replication group. If this argument is omitted, the default cache parameter group for the specified engine is used.

If you are running Redis version 3.2.4 or later, only one node group (shard), and want to use a default parameter group, we recommend that you specify the parameter group by name.

  • To create a Redis (cluster mode disabled) replication group, use CacheParameterGroupName=default.redis3.2.

  • To create a Redis (cluster mode enabled) replication group, use CacheParameterGroupName=default.redis3.2.cluster.on.

Type: String

Required: No

CacheSecurityGroupNames.CacheSecurityGroupName.N

A list of cache security group names to associate with this replication group.

Type: Array of strings

Required: No

CacheSubnetGroupName

The name of the cache subnet group to be used for the replication group.

Important

If you're going to launch your cluster in an Amazon VPC, you need to create a subnet group before you start creating a cluster. For more information, see Subnets and Subnet Groups.

Type: String

Required: No

Engine

The name of the cache engine to be used for the clusters in this replication group.

Type: String

Required: No

EngineVersion

The version number of the cache engine to be used for the clusters in this replication group. To view the supported cache engine versions, use the DescribeCacheEngineVersions operation.

Important: You can upgrade to a newer engine version (see Selecting a Cache Engine and Version) in the ElastiCache User Guide, but you cannot downgrade to an earlier engine version. If you want to use an earlier engine version, you must delete the existing cluster or replication group and create it anew with the earlier engine version.

Type: String

Required: No

NodeGroupConfiguration.NodeGroupConfiguration.N

A list of node group (shard) configuration options. Each node group (shard) configuration has the following: Slots, PrimaryAvailabilityZone, ReplicaAvailabilityZones, ReplicaCount.

If you're creating a Redis (cluster mode disabled) or a Redis (cluster mode enabled) replication group, you can use this parameter to individually configure each node group (shard), or you can omit this parameter.

Type: Array of NodeGroupConfiguration objects

Required: No

NotificationTopicArn

The Amazon Resource Name (ARN) of the Amazon Simple Notification Service (SNS) topic to which notifications are sent.

Note

The Amazon SNS topic owner must be the same as the cluster owner.

Type: String

Required: No

NumCacheClusters

The number of clusters this replication group initially has.

This parameter is not used if there is more than one node group (shard). You should use ReplicasPerNodeGroup instead.

If AutomaticFailoverEnabled is true, the value of this parameter must be at least 2. If AutomaticFailoverEnabled is false you can omit this parameter (it will default to 1), or you can explicitly set it to a value between 2 and 6.

The maximum permitted value for NumCacheClusters is 6 (primary plus 5 replicas).

Type: Integer

Required: No

NumNodeGroups

An optional parameter that specifies the number of node groups (shards) for this Redis (cluster mode enabled) replication group. For Redis (cluster mode disabled) either omit this parameter or set it to 1.

Default: 1

Type: Integer

Required: No

Port

The port number on which each member of the replication group accepts connections.

Type: Integer

Required: No

PreferredCacheClusterAZs.AvailabilityZone.N

A list of EC2 Availability Zones in which the replication group's clusters are created. The order of the Availability Zones in the list is the order in which clusters are allocated. The primary cluster is created in the first AZ in the list.

This parameter is not used if there is more than one node group (shard). You should use NodeGroupConfiguration instead.

Note

If you are creating your replication group in an Amazon VPC (recommended), you can only locate clusters in Availability Zones associated with the subnets in the selected subnet group.

The number of Availability Zones listed must equal the value of NumCacheClusters.

Default: system chosen Availability Zones.

Type: Array of strings

Required: No

PreferredMaintenanceWindow

Specifies the weekly time range during which maintenance on the cluster is performed. It is specified as a range in the format ddd:hh24:mi-ddd:hh24:mi (24H Clock UTC). The minimum maintenance window is a 60 minute period. Valid values for ddd are:

Specifies the weekly time range during which maintenance on the cluster is performed. It is specified as a range in the format ddd:hh24:mi-ddd:hh24:mi (24H Clock UTC). The minimum maintenance window is a 60 minute period.

Valid values for ddd are:

  • sun

  • mon

  • tue

  • wed

  • thu

  • fri

  • sat

Example: sun:23:00-mon:01:30

Type: String

Required: No

PrimaryClusterId

The identifier of the cluster that serves as the primary for this replication group. This cluster must already exist and have a status of available.

This parameter is not required if NumCacheClusters, NumNodeGroups, or ReplicasPerNodeGroup is specified.

Type: String

Required: No

ReplicasPerNodeGroup

An optional parameter that specifies the number of replica nodes in each node group (shard). Valid values are 0 to 5.

Type: Integer

Required: No

SecurityGroupIds.SecurityGroupId.N

One or more Amazon VPC security groups associated with this replication group.

Use this parameter only when you are creating a replication group in an Amazon Virtual Private Cloud (Amazon VPC).

Type: Array of strings

Required: No

SnapshotArns.SnapshotArn.N

A list of Amazon Resource Names (ARN) that uniquely identify the Redis RDB snapshot files stored in Amazon S3. The snapshot files are used to populate the new replication group. The Amazon S3 object name in the ARN cannot contain any commas. The new replication group will have the number of node groups (console: shards) specified by the parameter NumNodeGroups or the number of node groups configured by NodeGroupConfiguration regardless of the number of ARNs specified here.

Example of an Amazon S3 ARN: arn:aws:s3:::my_bucket/snapshot1.rdb

Type: Array of strings

Required: No

SnapshotName

The name of a snapshot from which to restore data into the new replication group. The snapshot status changes to restoring while the new replication group is being created.

Type: String

Required: No

SnapshotRetentionLimit

The number of days for which ElastiCache retains automatic snapshots before deleting them. For example, if you set SnapshotRetentionLimit to 5, a snapshot that was taken today is retained for 5 days before being deleted.

Default: 0 (i.e., automatic backups are disabled for this cluster).

Type: Integer

Required: No

SnapshotWindow

The daily time range (in UTC) during which ElastiCache begins taking a daily snapshot of your node group (shard).

Example: 05:00-09:00

If you do not specify this parameter, ElastiCache automatically chooses an appropriate time range.

Type: String

Required: No

Tags.Tag.N

A list of cost allocation tags to be added to this resource. A tag is a key-value pair.

Type: Array of Tag objects

Required: No

TransitEncryptionEnabled

A flag that enables in-transit encryption when set to true.

You cannot modify the value of TransitEncryptionEnabled after the cluster is created. To enable in-transit encryption on a cluster you must set TransitEncryptionEnabled to true when you create a cluster.

This parameter is valid only if the Engine parameter is redis, the EngineVersion parameter is 3.2.6, and the cluster is being created in an Amazon VPC.

If you enable in-transit encryption, you must also specify a value for CacheSubnetGroup.

Required: Only available when creating a replication group in an Amazon VPC using redis version 3.2.6.

Default: false

Important

For HIPAA compliance, you must specify TransitEncryptionEnabled as true, an AuthToken, and a CacheSubnetGroup.

Type: Boolean

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.

CacheClusterNotFound

The requested cluster ID does not refer to an existing cluster.

HTTP Status Code: 404

CacheParameterGroupNotFound

The requested cache parameter group name does not refer to an existing cache parameter group.

HTTP Status Code: 404

CacheSecurityGroupNotFound

The requested cache security group name does not refer to an existing cache security group.

HTTP Status Code: 404

CacheSubnetGroupNotFoundFault

The requested cache subnet group name does not refer to an existing cache subnet group.

HTTP Status Code: 400

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.

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

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

NodeQuotaForClusterExceeded

The request cannot be processed because it would exceed the allowed number of cache nodes in a single cluster.

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

ReplicationGroupAlreadyExists

The specified replication group already exists.

HTTP Status Code: 400

TagQuotaPerResourceExceeded

The request cannot be processed because it would cause the resource to have more than the allowed number of tags. The maximum number of tags permitted on a resource is 50.

HTTP Status Code: 400

Examples

CreateReplicationGroup - Redis (cluster mode disabled) Replication Group

The following example creates a Redis (cluster mode disabled) replication group with three nodes (NumCacheClusters=3), a primary and two read replicas. Because a single node group (shard) replication group technically could be either clustered or non-clustered, the parameter group default.redis3.2 is specified, making this is a non-clustered replication group.

Sample Request

https://elasticache.us-west-2.amazonaws.com/
   ?Action=CreateReplicationGroup 
   &CacheParameterGroup=default.redis3.2
   &Engine=redis
   &EngineVersion=3.2.4
   &NumCacheClusters=3
   &ReplicationGroupDescription=My%20replication%20group
   &ReplicationGroupId=my-repgroup
   &PrimaryClusterId=my-redis-primary
   &Version=2015-02-02
   &SignatureVersion=4
   &SignatureMethod=HmacSHA256
   &Timestamp=20150202T192317Z
   &X-Amz-Credential=<credential>

Sample Response

<CreateReplicationGroupResponse xmlns="http://elasticache.amazonaws.com/doc/2015-02-02/"> 
   <CreateReplicationGroupResult> 
      <ReplicationGroup> 
         <SnapshottingClusterId>my-redis-primary</SnapshottingClusterId> 
         <MemberClusters> 
            <ClusterId>my-redis-primary</ClusterId> 
         </MemberClusters> 
         <ReplicationGroupId>my-repgroup</ReplicationGroupId> 
         <Status>creating</Status> 
         <PendingModifiedValues /> 
         <Description>My replication group</Description> 
      </ReplicationGroup> 
   </CreateReplicationGroupResult> 
   <ResponseMetadata> 
      <RequestId>f3b7b32d-b9d2-11e3-8a16-7978bb24ffdf</RequestId> 
   </ResponseMetadata> 
</CreateReplicationGroupResponse>

Redis (cluster mode enabled) Replication Group - all shards same profile

The following example creates a Redis (cluster mode enabled) replication group with three node groups (shards) and four replica nodes in each node group (shard). Note the following parameters and their values.

  • EngineVersion=3.2.4

  • CacheParameterGroup=default.redis3.2.cluster.on

  • NumNodeGroups=3

  • ReplicasPerNodeGroup=4

Sample Request

https://elasticache.us-west-2.amazonaws.com/
   ?Action=CreateReplicationGroup 
   &CacheParameterGroup=default.redis3.2.cluster.on
   &Engine=redis
   &EngineVersion=3.2.4
   &ReplicationGroupDescription=My%20replication%20group
   &ReplicationGroupId=my-repgroup
   &NumNodeGroups=3
   &PrimaryClusterId=my-redis-primary
   &ReplicasPerNodeGroup=4
   &Version=2015-02-02
   &SignatureVersion=4
   &SignatureMethod=HmacSHA256
   &Timestamp=20150202T192317Z
   &X-Amz-Credential=<credential>

Redis (cluster mode enabled) Replication Group - each shard configured separately

The following example creates a Redis (cluster mode enabled) replication group with two node groups (shards). The first shard has two replica nodes and slots 0-8192. The second shard has one replica and slots 8193-16383. Note the following parameters and their values.

  • EngineVersion

  • CacheParameterGroup

  • NodeGroupConfiguration.NodeGroupConfiguration.n.PrimaryAvailabilityZone

  • NodeGroupConfiguration.NodeGroupConfiguration.n.ReplicaAvailabilityZones.AvailabilityZone.n

  • NodeGroupConfiguration.NodeGroupConfiguration.n.ReplicaCount

  • NodeGroupConfiguration.NodeGroupConfiguration.n.Slots

Sample Request

https://elasticache.us-west-2.amazonaws.com/
   ?Action=CreateReplicationGroup 
   &CacheParameterGroup=default.redis3.2.cluster.on
   &Engine=redis
   &EngineVersion=3.2.4
   &ReplicationGroupDescription=My%20replication%20group
   &ReplicationGroupId=my-repgroup
   &NodeGroupConfiguration.NodeGroupConfiguration.1.PrimaryAvailabilityZone=us-east-2a
   &NodeGroupConfiguration.NodeGroupConfiguration.1.ReplicaAvailabilityZones.AvailabilityZone.1=us-east-2b
   &NodeGroupConfiguration.NodeGroupConfiguration.1.ReplicaAvailabilityZones.AvailabilityZone.2=us-east-2c
   &NodeGroupConfiguration.NodeGroupConfiguration.1.ReplicaCount=2
   &NodeGroupConfiguration.NodeGroupConfiguration.1.Slots=0-8192
   &NodeGroupConfiguration.NodeGroupConfiguration.2.PrimaryAvailabilityZone=us-east-2b
   &NodeGroupConfiguration.NodeGroupConfiguration.2.ReplicaAvailabilityZones.AvailabilityZone.1=us-east-2d
   &NodeGroupConfiguration.NodeGroupConfiguration.2.ReplicaCount=1
   &NodeGroupConfiguration.NodeGroupConfiguration.2.Slots=8193-16383
   &PrimaryClusterId=my-redis-primary
   &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: