AWS Elasticache Redis Terraform module

Terraform module which creates Elasticache resources on AWS

Root module calls these modules which can also be used separately to create independent resources:

• cache_parameter_group - creates Elasticache parameter group
• cache_subnet_group - creates Elasticache subnet group
• cache_user - creates Elasticache user
• cache_user_group - creates Elasticache user group

Usage

module "elasticache" {
  source = "osgurisdosre/elasticache/aws"

  create_cache         = true
  replication_group_id = "redis-app"
  description_redis    = "Redis App"
  node_type            = "cache.t2.micro"
  security_group_ids   = ["sg-0000000000000", "sg-111111111111111"]
  num_cache_clusters   = 3

  # Cache subnet group
  create_elasticache_subnet_group = true
  subnet_group_name               = "elasticache-subnets"
  subnet_ids                      = ["subnet-123456789", "subnet-987654321", "subnet-123321123"]

  # Cache parameter group
  create_elasticache_parameter_group = true
  parameters = [{
    name  = "activerehashing"
    value = "yes"
  }]

  # Cache user
  create_elasticache_user = true
  create_cache_password   = true

  user_name     = "userapp"
  user_id       = "userapp"
  access_string = "on ~* +@all"
  authentication_mode = [{
    type = "password"
  }]

  # Cache user group
  create_elasticache_user_group = true
  user_group_id                 = "app"
}

Serverless

module "elastic_serverlesss" {
  source = "osgurisdosre/elasticache/aws" 
  create_elasticache_serverless = true
  
  serverless_name    = "redis-serverless"
  description_serverless = "serverless"
  enabled_limits = true
  cache_usage_limits = {
    data_storage = {
      maximum = 1000
      unit    = "GB"
    }
    ecpu_per_second = {
     maximum = 1000
    }
  }
  daily_snapshot_time      = "09:00"
  kms_key_id               = aws_kms_key.test.arn
  major_engine_version     = "7"
  snapshot_retention_limit = 1
  security_group_ids       = ["sg-0000000000000", "sg-111111111111111"]
  subnet_ids               = ["subnet-123456789", "subnet-987654321", "subnet-123321123"]
  user_group_id            = module.user_group.elasticache_user_group_id
  tags = {
    "Environment" = "prd"
  }
}

Conditional creation

module "elasticache" {
  source                    = "osgurisdosre/documentdb/aws"
  
  # Disable creation of Elasticache
  create_cache                = false

  # Enable creation of a random password
  create_cache_password       = true

  # Enable creation of subnet group
  create_elasticache_subnet_group    = true
  
  # Enable creation of parameter group
  create_elasticache_parameter_group = true

  # Enable creation of user
  create_elasticache_user  = true

  # Enable creation of user group
  create_elasticache_user_group = true
  
  # Enable creation of serverless
  create_elasticache_serverless = true
 
  #Enable modification in cache_usage_limits
  enabled_limits = true
}

Examples

To-do:

Notes

1. This module does not create Elasticache security group. Use terraform-aws-security-group module for this.
2. By default, the variable create_db_password is set to true. Therefore, even if the user provides a password, it will not be read. The create_db_password variable should be set to false and the passwords variable should have a non-null value to be read and used.
3. By default, the create_elasticache_serverless variable is set false

Requirements

Name	Version
terraform	>= 1.4
aws	>= 5.40
random	>= 3.1

Providers

Name	Version
aws	>= 5.40
random	>= 3.1

Modules

Name	Source	Version
elasticache_parameter_group	./modules/cache_parameter_group	n/a
elasticache_subnet_group	./modules/cache_subnet_group	n/a
elasticache_user	./modules/cache_user	n/a
elasticache_user_group	./modules/cache_user_group	n/a

Resources

Name	Type
aws_elasticache_replication_group.this	resource
aws_elasticache_serverless_cache.this	resource
random_password.master_password	resource

Inputs

Name	Description	Type	Default	Required
access_string	Access permissions string used for this user.	string	null	no
apply_immediately	Specifies whether any modifications are applied immediately, or during the next maintenance window.	bool	false	no
at_rest_encryption_enabled	Whether to enable encryption at rest.	bool	true	no
auth_token	Password used to access a password protected server	string	null	no
authentication_mode	Denotes the user's authentication properties. Possible of type options are: password, no-password-required or iam.	list(object({ type = optional(string) passwords = optional(string) }))	[ { "passwords": null, "type": null } ]	no
auto_minor_version_upgrade	Specifies whether minor version engine upgrades will be applied automatically to the underlying	bool	false	no
automatic_failover_enabled	Specifies whether a read-only replica will be automatically promoted to read/write primary if the existing primary fails.	bool	true	no
cache_usage_limits	Sets the cache usage limits for storage and ElastiCache Processing Units for the cache.(data_storage,ecpu_per_second)	any	{}	no
create	Create the resource?	bool	true	no
create_cache	Create the elasticache Redis?	bool	false	no
create_cache_password	Create the password?	bool	false	no
create_elasticache_parameter_group	Create the parameter group?	bool	false	no
create_elasticache_replication_group	Create the replication group?	bool	false	no
create_elasticache_serverless	Create the elasticache Redis serverless?	bool	false	no
create_elasticache_subnet_group	Create the subnet group?	bool	false	no
create_elasticache_user	Create the user?	bool	false	no
create_elasticache_user_group	Create the user group?	bool	false	no
daily_snapshot_time	The daily time that snapshots will be created from the new serverless cache.(Only for the serverless module)	string	"03:00"	no
data_tiering_enabled	Enables data tiering	bool	false	no
description_parameter	The description of the ElastiCache parameter group.	string	null	no
description_redis	User-created description for the replication group. Must not be empty	string	""	no
description_serverless	User-created description for the serverless. Must not be empty	string	""	no
description_subnet	The Description of the ElastiCache Subnet Group.	string	null	no
enabled_limits	Enable customization of cache_usage_limits(Only for the serverless module)	bool	false	no
engine	Name of the cache engine to be used for the clusters in this replication group.	string	"redis"	no
engine_version	Version number of the cache engine to be used for the cache clusters in this replication group.	string	"6.x"	no
family	The family of the ElastiCache parameter group.	string	"redis6.x"	no
final_snapshot_identifier	The name of your final node group (shard) snapshot.	string	null	no
global_replication_group_id	The ID of the global replication group to which this replication group should belong.	string	null	no
kms_key_id	The ARN of the key that you wish to use if encrypting at rest.	string	null	no
log_delivery_configuration	block allows the streaming of Redis SLOWLOG or Redis Engine Log to CloudWatch Log	list(map(string))	[]	no
maintenance_window	Specifies the weekly time range for when maintenance on the cache cluster is performed.	string	"sat:03:00-sat:06:00"	no
major_engine_version	The version of the cache engine that will be used to create the serverless cache.(Only for the serverless module)	string	"7"	no
multi_az_enabled	Specifies whether to enable Multi-AZ Support for the replication group.	bool	false	no
node_type	Instance class to be used.	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.	number	3	no
num_node_groups	Number of node groups (shards) for this Redis replication group.	number	null	no
parameter_group_name	The name of the ElastiCache parameter group.	string	null	no
parameters	List of DB parameters to apply	list(map(string))	[]	no
password	Password for the user.	list(string)	[]	no
password_create	Password Create	string	null	no
port	Port number on which each of the cache nodes will accept connections.	number	6379	no
preferred_cache_cluster_azs	List of EC2 availability zones in which the replication group's cache clusters will be created.	list(string)	null	no
random_password_length	The length of the string desired.	number	16	no
replicas_per_node_group	Number of replica nodes in each node group.	number	null	no
replication_group_id	Replication group identifier. This parameter is stored as a lowercase string.	string	null	no
security_group_ids	One or more Amazon VPC security groups associated with this replication group.	list(string)	[]	no
security_group_names	List of cache security group names to associate with this replication group.	list(string)	null	no
serverless_name	Name Redis Serverless. This parameter is stored as a lowercase string.	string	null	no
snapshot_arns_to_restore	The list of ARN(s) of the snapshot that the new serverless cache will be created from(Only for the serverless module)	list(string)	null	no
snapshot_name	Name of a snapshot from which to restore data into the new node group.	string	null	no
snapshot_retention_limit	Number of days for which ElastiCache will retain automatic cache cluster snapshots before deleting them.	number	7	no
snapshot_window	Daily time range (in UTC) during which ElastiCache will begin taking a daily snapshot of your cache cluster.	string	"00:00-02:00"	no
subnet_group_name	The Name of the ElastiCache Subnet Group.	string	null	no
subnet_ids	The Subnet IDs of the ElastiCache Subnet Group.	list(string)	[ null ]	no
tags	A map of tags to add to all resources	map(string)	{}	no
transit_encryption_enabled	Whether to enable encryption in transit.	bool	true	no
user_group_id	The user group identifier.	string	null	no
user_group_ids	User Group ID to associate with the replication group.	list(string)	null	no
user_id	The ID of the user.	string	null	no
user_name	The username of the user.	string	null	no

Outputs

Name	Description
cache_instance_endpoint	The DNS address of the Primary Cache
cache_instance_password	The cache password (this password may be old, because Terraform doesn't track it after initial creation)
db_instance_endpoint_reader	The DNS address of the Reader Cache

Authors

Module is maintained by Emidio Neto, Leonardo Jardim and Yuri Azeredo

License

Apache 2 Licensed. See LICENSE for full details.