AWS ElastiCache Terraform module

Terraform module which creates AWS ElastiCache resources.

Usage

See examples directory for working examples to reference:

Memcached Cluster

module "elasticache" {
  source = "terraform-aws-modules/elasticache/aws"

  cluster_id               = "example-memcached"
  create_cluster           = true
  create_replication_group = false

  engine          = "memcached"
  engine_version  = "1.6.17"
  node_type       = "cache.t4g.small"
  num_cache_nodes = 2
  az_mode         = "cross-az"

  maintenance_window = "sun:05:00-sun:09:00"
  apply_immediately  = true

  # Security group
  vpc_id = module.vpc.vpc_id
  security_group_rules = {
    ingress_vpc = {
      # Default type is `ingress`
      # Default port is based on the default engine port
      description = "VPC traffic"
      cidr_ipv4   = module.vpc.vpc_cidr_block
    }
  }

  # Subnet Group
  subnet_ids = module.vpc.private_subnets

  # Parameter Group
  create_parameter_group = true
  parameter_group_family = "memcached1.6"
  parameters = [
    {
      name  = "idle_timeout"
      value = 60
    }
  ]

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}

Redis Cluster

module "elasticache" {
  source = "terraform-aws-modules/elasticache/aws"

  cluster_id               = "example-redis"
  create_cluster           = true
  create_replication_group = false

  engine_version = "7.1"
  node_type      = "cache.t4g.small"

  maintenance_window = "sun:05:00-sun:09:00"
  apply_immediately  = true

  # Security group
  vpc_id = module.vpc.vpc_id
  security_group_rules = {
    ingress_vpc = {
      # Default type is `ingress`
      # Default port is based on the default engine port
      description = "VPC traffic"
      cidr_ipv4   = module.vpc.vpc_cidr_block
    }
  }

  # Subnet Group
  subnet_ids = module.vpc.private_subnets

  # Parameter Group
  create_parameter_group = true
  parameter_group_family = "redis7"
  parameters = [
    {
      name  = "latency-tracking"
      value = "yes"
    }
  ]

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}

Redis Cluster Mode

module "elasticache" {
  source = "terraform-aws-modules/elasticache/aws"

  replication_group_id = "example-redis-cluster"

  # Cluster mode
  cluster_mode_enabled       = true
  num_node_groups            = 2
  replicas_per_node_group    = 3
  automatic_failover_enabled = true
  multi_az_enabled           = true

  maintenance_window = "sun:05:00-sun:09:00"
  apply_immediately  = true

  # Security group
  vpc_id = module.vpc.vpc_id
  security_group_rules = {
    ingress_vpc = {
      # Default type is `ingress`
      # Default port is based on the default engine port
      description = "VPC traffic"
      cidr_ipv4   = module.vpc.vpc_cidr_block
    }
  }

  # Subnet Group
  subnet_ids = module.vpc.private_subnets

  # Parameter Group
  create_parameter_group = true
  parameter_group_family = "redis7"
  parameters = [
    {
      name  = "latency-tracking"
      value = "yes"
    }
  ]

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}

Redis Global Replication Group

module "elasticache_primary" {
  source = "terraform-aws-modules/elasticache/aws"

  replication_group_id                    = "example-redis-global-replication-group"
  create_primary_global_replication_group = true

  engine_version = "7.1"
  node_type      = "cache.r7g.large"

  # Security group
  vpc_id = module.vpc.vpc_id
  security_group_rules = {
    ingress_vpc = {
      # Default type is `ingress`
      # Default port is based on the default engine port
      description = "VPC traffic"
      cidr_ipv4   = module.vpc.vpc_cidr_block
    }
  }

  # Subnet Group
  subnet_ids = module.vpc.private_subnets

  # Parameter Group
  create_parameter_group = true
  parameter_group_family = "redis7"

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}

module "elasticache_secondary" {
  source = "terraform-aws-modules/elasticache/aws"

  providers = {
    aws = aws.other_region
  }

  replication_group_id        = "example-redis-global-replication-group"
  global_replication_group_id = module.elasticache_primary.global_replication_group_id

  # Security group
  vpc_id = module.vpc.vpc_id
  security_group_rules = {
    ingress_vpc = {
      # Default type is `ingress`
      # Default port is based on the default engine port
      description = "VPC traffic"
      cidr_ipv4   = module.vpc.vpc_cidr_block
    }
  }

  # Subnet Group
  subnet_ids = module.vpc.private_subnets

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}

Redis Replication Group

module "elasticache" {
  source = "terraform-aws-modules/elasticache/aws"

  replication_group_id = "example-redis-replication-group"

  engine_version = "7.1"
  node_type      = "cache.t4g.small"

  transit_encryption_enabled = true
  auth_token                 = "PickSomethingMoreSecure123!"
  maintenance_window         = "sun:05:00-sun:09:00"
  apply_immediately          = true

  # Security group
  vpc_id = module.vpc.vpc_id
  security_group_rules = {
    ingress_vpc = {
      # Default type is `ingress`
      # Default port is based on the default engine port
      description = "VPC traffic"
      cidr_ipv4   = module.vpc.vpc_cidr_block
    }
  }

  # Subnet Group
  subnet_ids = module.vpc.private_subnets

  # Parameter Group
  create_parameter_group = true
  parameter_group_family = "redis7"
  parameters = [
    {
      name  = "latency-tracking"
      value = "yes"
    }
  ]

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}

Examples

Examples codified under the examples are intended to give users references for how to use the module(s) as well as testing/validating changes to the source code of the module. If contributing to the project, please be sure to make any appropriate updates to the relevant examples to allow maintainers to test your changes and to keep the examples up to date for users. Thank you!

• Memcached Cluster
• Redis Cluster
• Redis Cluster Mode
• Redis Global Replication Group
• Redis Replication Group

Requirements

Name	Version
terraform	>= 1.0
aws	>= 5.47
random	>= 3.0

Providers

Name	Version
aws	>= 5.47
random	>= 3.0

Modules

No modules.

Resources

Name	Type
aws_cloudwatch_log_group.this	resource
aws_elasticache_cluster.this	resource
aws_elasticache_global_replication_group.this	resource
aws_elasticache_parameter_group.this	resource
aws_elasticache_replication_group.global	resource
aws_elasticache_replication_group.this	resource
aws_elasticache_subnet_group.this	resource
aws_security_group.this	resource
aws_vpc_security_group_egress_rule.this	resource
aws_vpc_security_group_ingress_rule.this	resource
random_id.this	resource

Inputs

Name	Description	Type	Default	Required
apply_immediately	Whether any database modifications are applied immediately, or during the next maintenance window. Default is false	bool	null	no
at_rest_encryption_enabled	Whether to enable encryption at rest	bool	true	no
auth_token	The password used to access a password protected server. Can be specified only if transit_encryption_enabled = true	string	null	no
auth_token_update_strategy	Strategy to use when updating the auth_token. Valid values are SET, ROTATE, and DELETE. Defaults to ROTATE	string	null	no
auto_minor_version_upgrade	Specifies whether minor version engine upgrades will be applied automatically to the underlying Cache Cluster instances during the maintenance window. Only supported for engine type redis and if the engine version is 6 or higher. Defaults to true	bool	null	no
automatic_failover_enabled	Specifies whether a read-only replica will be 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. Must be enabled for Redis (cluster mode enabled) replication groups	bool	null	no
availability_zone	Availability Zone for the cache cluster. If you want to create cache nodes in multi-az, use preferred_availability_zones instead	string	null	no
az_mode	Whether the nodes in this Memcached node group are created in a single Availability Zone or created across multiple Availability Zones in the cluster's region. Valid values for this parameter are single-az or cross-az, default is single-az	string	null	no
cluster_id	Group identifier. ElastiCache converts this name to lowercase. Changing this value will re-create the resource	string	""	no
cluster_mode_enabled	Whether to enable Redis [cluster mode https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/Replication.Redis-RedisCluster.html]	bool	false	no
create	Determines whether resources will be created (affects all resources)	bool	true	no
create_cluster	Determines whether an ElastiCache cluster will be created or not	bool	false	no
create_parameter_group	Determines whether the ElastiCache parameter group will be created or not	bool	false	no
create_primary_global_replication_group	Determines whether an primary ElastiCache global replication group will be created	bool	false	no
create_replication_group	Determines whether an ElastiCache replication group will be created or not	bool	true	no
create_secondary_global_replication_group	Determines whether an secondary ElastiCache global replication group will be created	bool	false	no
create_security_group	Determines if a security group is created	bool	true	no
create_subnet_group	Determines whether the Elasticache subnet group will be created or not	bool	true	no
data_tiering_enabled	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	bool	null	no
description	User-created description for the replication group	string	null	no
engine	Name of the cache engine to be used for this cache cluster. Valid values are memcached or redis	string	"redis"	no
engine_version	Version number of the cache engine to be used. If not set, defaults to the latest version	string	null	no
final_snapshot_identifier	(Redis only) Name of your final cluster snapshot. If omitted, no final snapshot will be made	string	null	no
global_replication_group_id	The ID of the global replication group to which this replication group should belong	string	null	no
ip_discovery	The IP version to advertise in the discovery protocol. Valid values are ipv4 or ipv6	string	null	no
kms_key_arn	The ARN of the key that you wish to use if encrypting at rest. If not supplied, uses service managed encryption. Can be specified only if at_rest_encryption_enabled = true	string	null	no
log_delivery_configuration	(Redis only) Specifies the destination and format of Redis SLOWLOG or Redis Engine Log	any	{ "slow-log": { "destination_type": "cloudwatch-logs", "log_format": "json" } }	no
maintenance_window	Specifies the weekly time range for when maintenance on the cache cluster is performed. The format is ddd:hh24:mi-ddd:hh24:mi (24H Clock UTC)	string	null	no
multi_az_enabled	Specifies whether to enable Multi-AZ Support for the replication group. If true, automatic_failover_enabled must also be enabled. Defaults to false	bool	false	no
network_type	The IP versions for cache cluster connections. Valid values are ipv4, ipv6 or dual_stack	string	null	no
node_type	The instance class used. For Memcached, changing this value will re-create the resource	string	null	no
notification_topic_arn	ARN of an SNS topic to send ElastiCache notifications to	string	null	no
num_cache_clusters	Number of cache clusters (primary and replicas) this replication group will have. If Multi-AZ is enabled, the value of this parameter must be at least 2. Updates will occur before other modifications. Conflicts with num_node_groups. Defaults to 1	number	null	no
num_cache_nodes	The initial number of cache nodes that the cache cluster will have. For Redis, this value must be 1. For Memcached, this value must be between 1 and 40. If this number is reduced on subsequent runs, the highest numbered nodes will be removed	number	1	no
num_node_groups	Number of node groups (shards) for this Redis replication group. Changing this number will trigger a resizing operation before other settings modifications	number	null	no
outpost_mode	Specify the outpost mode that will apply to the cache cluster creation. Valid values are single-outpost and cross-outpost, however AWS currently only supports single-outpost mode	string	null	no
parameter_group_description	The description of the ElastiCache parameter group. Defaults to Managed by Terraform	string	null	no
parameter_group_family	The family of the ElastiCache parameter group	string	""	no
parameter_group_name	The name of the parameter group. If create_parameter_group is true, this is the name assigned to the parameter group created. Otherwise, this is the name of an existing parameter group	string	null	no
parameters	List of ElastiCache parameters to apply	list(map(string))	[]	no
port	The port number on which each of the cache nodes will accept connections. For Memcached the default is 11211, and for Redis the default port is 6379	number	null	no
preferred_availability_zones	List of the Availability Zones in which cache nodes are created	list(string)	[]	no
preferred_cache_cluster_azs	List of EC2 availability zones in which the replication group's cache clusters will be created. The order of the availability zones in the list is considered. The first item in the list will be the primary node. Ignored when updating	list(string)	[]	no
preferred_outpost_arn	(Required if outpost_mode is specified) The outpost ARN in which the cache cluster will be created	string	null	no
replicas_per_node_group	Number of replica nodes in each node group. Changing this number will trigger a resizing operation before other settings modifications. Valid values are 0 to 5	number	null	no
replication_group_id	Replication group identifier. When create_replication_group is set to true, this is the ID assigned to the replication group created. When create_replication_group is set to false, this is the ID of an externally created replication group	string	null	no
security_group_description	Description of the security group created	string	null	no
security_group_ids	One or more VPC security groups associated with the cache cluster	list(string)	[]	no
security_group_name	Name to use on security group created	string	null	no
security_group_names	Names of one or more Amazon VPC security groups associated with this replication group	list(string)	[]	no
security_group_rules	Security group ingress and egress rules to add to the security group created	any	{}	no
security_group_tags	A map of additional tags to add to the security group created	map(string)	{}	no
security_group_use_name_prefix	Determines whether the security group name (security_group_name) is used as a prefix	bool	true	no
snapshot_arns	(Redis only) Single-element string list containing an Amazon Resource Name (ARN) of a Redis RDB snapshot file stored in Amazon S3	list(string)	[]	no
snapshot_name	(Redis only) Name of a snapshot from which to restore data into the new node group. Changing snapshot_name forces a new resource	string	null	no
snapshot_retention_limit	(Redis only) Number of days for which ElastiCache will retain automatic cache cluster snapshots before deleting them	number	null	no
snapshot_window	(Redis only) Daily time range (in UTC) during which ElastiCache will begin taking a daily snapshot of your cache cluster. Example: 05:00-09:00	string	null	no
subnet_group_description	Description for the Elasticache subnet group	string	null	no
subnet_group_name	The name of the subnet group. If create_subnet_group is true, this is the name assigned to the subnet group created. Otherwise, this is the name of an existing subnet group	string	null	no
subnet_ids	List of VPC Subnet IDs for the Elasticache subnet group	list(string)	[]	no
tags	A map of tags to add to all resources	map(string)	{}	no
transit_encryption_enabled	Enable encryption in-transit. Supported only with Memcached versions 1.6.12 and later, running in a VPC	bool	true	no
transit_encryption_mode	A setting that enables clients to migrate to in-transit encryption with no downtime. Valid values are preferred and required	string	null	no
user_group_ids	User Group ID to associate with the replication group. Only a maximum of one (1) user group ID is valid	list(string)	null	no
vpc_id	Identifier of the VPC where the security group will be created	string	null	no

Outputs

Name	Description
cloudwatch_log_group_arn	Arn of cloudwatch log group created
cloudwatch_log_group_name	Name of cloudwatch log group created
cluster_address	(Memcached only) DNS name of the cache cluster without the port appended
cluster_arn	The ARN of the ElastiCache Cluster
cluster_cache_nodes	List of node objects including id, address, port and availability_zone
cluster_configuration_endpoint	(Memcached only) Configuration endpoint to allow host discovery
cluster_engine_version_actual	Because ElastiCache pulls the latest minor or patch for a version, this attribute returns the running version of the cache engine
global_replication_group_arn	ARN of the created ElastiCache Global Replication Group
global_replication_group_engine_version_actual	The full version number of the cache engine running on the members of this global replication group
global_replication_group_id	ID of the ElastiCache Global Replication Group
global_replication_group_node_groups	Set of node groups (shards) on the global replication group
parameter_group_arn	The AWS ARN associated with the parameter group
parameter_group_id	The ElastiCache parameter group name
replication_group_arn	ARN of the created ElastiCache Replication Group
replication_group_coniguration_endpoint_address	Address of the replication group configuration endpoint when cluster mode is enabled
replication_group_engine_version_actual	Because ElastiCache pulls the latest minor or patch for a version, this attribute returns the running version of the cache engine
replication_group_id	ID of the ElastiCache Replication Group
replication_group_member_clusters	Identifiers of all the nodes that are part of this replication group
replication_group_primary_endpoint_address	Address of the endpoint for the primary node in the replication group, if the cluster mode is disabled
replication_group_reader_endpoint_address	Address of the endpoint for the reader node in the replication group, if the cluster mode is disabled
security_group_arn	Amazon Resource Name (ARN) of the security group
security_group_id	ID of the security group
subnet_group_name	The ElastiCache subnet group name

License

Apache-2.0 Licensed. See LICENSE.