createReplicationGroup

Creates a Valkey or Redis OSS (cluster mode disabled) or a Valkey or Redis OSS (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 Valkey or Redis OSS (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 Valkey or Redis OSS 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 Valkey or Redis OSS 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 Valkey or Redis OSS (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 use scaling. For more information, see Scaling self-designed clusters in the ElastiCache User Guide.

This operation is valid for Valkey and Redis OSS only.

Samples

import aws.sdk.kotlin.services.elasticache.model.NodeGroupConfiguration
fun main() { 
   //sampleStart 
   // Creates a Redis replication group with 3 nodes.
val resp = elastiCacheClient.createReplicationGroup {
    replicationGroupId = "my-redis-rg"
    replicationGroupDescription = "A Redis replication group."
    automaticFailoverEnabled = true
    numCacheClusters = 3
    cacheNodeType = "cache.m3.medium"
    engine = "redis"
    engineVersion = "2.8.24"
    snapshotRetentionLimit = 30
} 
   //sampleEnd
}

import aws.sdk.kotlin.services.elasticache.model.NodeGroupConfiguration
fun main() { 
   //sampleStart 
   // Creates a Redis (cluster mode enabled) replication group with two shards. One shard has one read
// replica node and the other shard has two read replicas.
val resp = elastiCacheClient.createReplicationGroup {
    replicationGroupId = "clustered-redis-rg"
    replicationGroupDescription = "A multi-sharded replication group"
    numNodeGroups = 2
    nodeGroupConfiguration = listOf<NodeGroupConfiguration>(
        NodeGroupConfiguration {
            slots = "0-8999"
            primaryAvailabilityZone = "us-east-1c"
            replicaCount = 1
            replicaAvailabilityZones = listOf<String>(
                "us-east-1b"
            )
        },
        NodeGroupConfiguration {
            slots = "9000-16383"
            primaryAvailabilityZone = "us-east-1a"
            replicaCount = 2
            replicaAvailabilityZones = listOf<String>(
                "us-east-1a",
                "us-east-1c"
            )
        }            
    )
    cacheNodeType = "cache.m3.medium"
    engine = "redis"
    engineVersion = "3.2.4"
    cacheParameterGroupName = "default.redis3.2.cluster.on"
    autoMinorVersionUpgrade = true
    snapshotRetentionLimit = 8
} 
   //sampleEnd
}