CreateReplicationGroup - Amazon ElastiCache

CreateReplicationGroup

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

This API can be used to create a standalone regional replication group or a secondary replication group associated with a Global datastore.

A Redis (cluster mode disabled) replication group is a collection of nodes, where one of the nodes 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 cluster is comprised of from 1 to 90 shards (API/CLI: node groups). Each shard has a primary node and up to 5 read-only replica nodes. The configuration can range from 90 shards and 0 replicas to 15 shards and 5 replicas, which is the maximum number or replicas allowed.

The node or shard limit can be increased to a maximum of 500 per cluster if the Redis engine version is 5.0.6 or higher. For example, you can choose to configure a 500 node cluster that ranges between 83 shards (one primary and 5 replicas per shard) and 500 shards (single primary and no replicas). Make sure there are enough available IP addresses to accommodate the increase. Common pitfalls include the subnets in the subnet group have too small a CIDR range or the subnets are shared and heavily used by other clusters. For more information, see Creating a Subnet Group. For versions below 5.0.6, the limit is 250 per cluster.

To request a limit increase, see Amazon Service Limits and choose the limit type Nodes per cluster per instance type.

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. If you need to increase or decrease the number of node groups (console: shards), you can avail yourself of ElastiCache for Redis' scaling. For more information, see Scaling ElastiCache for Redis Clusters 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 40 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, 4.x or later.

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.

  • The only permitted printable special characters are !, &, #, $, ^, <, >, and -. Other printable special characters cannot be used in the AUTH token.

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.

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

Default: false

Type: Boolean

Required: No

AutoMinorVersionUpgrade

 If you are running Redis engine version 6.0 or later, set this parameter to yes if you want to opt-in to the next auto minor version upgrade campaign. This parameter is disabled for previous versions. 

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:

      M7g node types: cache.m7g.large, cache.m7g.xlarge, cache.m7g.2xlarge, cache.m7g.4xlarge, cache.m7g.8xlarge, cache.m7g.12xlarge, cache.m7g.16xlarge

      Note

      For region availability, see Supported Node Types

      M6g node types (available only for Redis engine version 5.0.6 onward and for Memcached engine version 1.5.16 onward): cache.m6g.large, cache.m6g.xlarge, cache.m6g.2xlarge, cache.m6g.4xlarge, cache.m6g.8xlarge, cache.m6g.12xlarge, cache.m6g.16xlarge

      M5 node types: cache.m5.large, cache.m5.xlarge, cache.m5.2xlarge, cache.m5.4xlarge, cache.m5.12xlarge, cache.m5.24xlarge

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

      T4g node types (available only for Redis engine version 5.0.6 onward and Memcached engine version 1.5.16 onward): cache.t4g.micro, cache.t4g.small, cache.t4g.medium

      T3 node types: cache.t3.micro, cache.t3.small, cache.t3.medium

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

    • Previous generation: (not recommended. Existing clusters are still supported but creation of new clusters is not supported for these types.)

      T1 node types: cache.t1.micro

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

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

  • Compute optimized:

    • Previous generation: (not recommended. Existing clusters are still supported but creation of new clusters is not supported for these types.)

      C1 node types: cache.c1.xlarge

  • Memory optimized:

    • Current generation:

      R7g node types: cache.r7g.large, cache.r7g.xlarge, cache.r7g.2xlarge, cache.r7g.4xlarge, cache.r7g.8xlarge, cache.r7g.12xlarge, cache.r7g.16xlarge

      Note

      For region availability, see Supported Node Types

      R6g node types (available only for Redis engine version 5.0.6 onward and for Memcached engine version 1.5.16 onward): cache.r6g.large, cache.r6g.xlarge, cache.r6g.2xlarge, cache.r6g.4xlarge, cache.r6g.8xlarge, cache.r6g.12xlarge, cache.r6g.16xlarge

      R5 node types: cache.r5.large, cache.r5.xlarge, cache.r5.2xlarge, cache.r5.4xlarge, cache.r5.12xlarge, cache.r5.24xlarge

      R4 node types: cache.r4.large, cache.r4.xlarge, cache.r4.2xlarge, cache.r4.4xlarge, cache.r4.8xlarge, cache.r4.16xlarge

    • Previous generation: (not recommended. Existing clusters are still supported but creation of new clusters is not supported for these types.)

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

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

Additional node type info

  • All current generation instance types are created in Amazon VPC by default.

  • Redis append-only files (AOF) are not supported for T1 or T2 instances.

  • Redis Multi-AZ with automatic failover is not supported on T1 instances.

  • Redis configuration variables appendonly and appendfsync are not supported on Redis version 2.8.22 and later.

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

ClusterMode

Enabled or Disabled. To modify cluster mode from Disabled to Enabled, you must first set the cluster mode to Compatible. Compatible mode allows your Redis clients to connect using both cluster mode enabled and cluster mode disabled. After you migrate all Redis clients to use cluster mode enabled, you can then complete cluster mode configuration and set the cluster mode to Enabled.

Type: String

Valid Values: enabled | disabled | compatible

Required: No

DataTieringEnabled

Enables data tiering. Data tiering is only supported for replication groups using the r6gd node type. This parameter must be set to true when using r6gd nodes. For more information, see Data tiering.

Type: Boolean

Required: No

Engine

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

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

GlobalReplicationGroupId

The name of the Global datastore

Type: String

Required: No

IpDiscovery

The network type you choose when creating a replication group, either ipv4 | ipv6. IPv6 is supported for workloads using Redis engine version 6.2 onward or Memcached engine version 1.6.6 on all instances built on the Nitro system.

Type: String

Valid Values: ipv4 | ipv6

Required: No

KmsKeyId

The ID of the KMS key used to encrypt the disk in the cluster.

Type: String

Required: No

LogDeliveryConfigurations.LogDeliveryConfigurationRequest.N

Specifies the destination, format and type of the logs.

Type: Array of LogDeliveryConfigurationRequest objects

Required: No

MultiAZEnabled

A flag indicating if you have Multi-AZ enabled to enhance fault tolerance. For more information, see Minimizing Downtime: Multi-AZ.

Type: Boolean

Required: No

NetworkType

Must be either ipv4 | ipv6 | dual_stack. IPv6 is supported for workloads using Redis engine version 6.2 onward or Memcached engine version 1.6.6 on all instances built on the Nitro system.

Type: String

Valid Values: ipv4 | ipv6 | dual_stack

Required: No

NodeGroupConfiguration.NodeGroupConfiguration.N

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

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. However, it is required when seeding a Redis (cluster mode enabled) cluster from a S3 rdb file. You must configure each node group (shard) using this parameter because you must specify the slots for each node group.

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 (1 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:

  • 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

ServerlessCacheSnapshotName

The name of the snapshot used to create a replication group. Available for Redis only.

Type: String

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 tags to be added to this resource. Tags are comma-separated key,value pairs (e.g. Key=myKey, Value=myKeyValue. You can include multiple tags as shown following: Key=myKey, Value=myKeyValue Key=mySecondKey, Value=mySecondKeyValue. Tags on replication groups will be replicated to all nodes.

Type: Array of Tag objects

Required: No

TransitEncryptionEnabled

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

This parameter is valid only if the Engine parameter is redis, the EngineVersion parameter is 3.2.6, 4.x or later, 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, 4.x or later.

Default: false

Important

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

Type: Boolean

Required: No

TransitEncryptionMode

A setting that allows you to migrate your clients to use in-transit encryption, with no downtime.

When setting TransitEncryptionEnabled to true, you can set your TransitEncryptionMode to preferred in the same request, to allow both encrypted and unencrypted connections at the same time. Once you migrate all your Redis clients to use encrypted connections you can modify the value to required to allow encrypted connections only.

Setting TransitEncryptionMode to required is a two-step process that requires you to first set the TransitEncryptionMode to preferred, after that you can set TransitEncryptionMode to required.

This process will not trigger the replacement of the replication group.

Type: String

Valid Values: preferred | required

Required: No

UserGroupIds.member.N

The user group to associate with the replication group.

Type: Array of strings

Array Members: Minimum number of 1 item.

Length Constraints: Minimum length of 1.

Pattern: [a-zA-Z][a-zA-Z0-9\-]*

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

GlobalReplicationGroupNotFoundFault

The Global datastore does not exist

HTTP Status Code: 404

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

InvalidGlobalReplicationGroupState

The Global datastore is not available or in primary-only 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

InvalidUserGroupState

The user group is not in an active 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 90

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

UserGroupNotFound

The user group was not found or does not exist

HTTP Status Code: 404

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: