aws_elasticache_cluster

Provides an ElastiCache Cluster resource.

Changes to a Cache Cluster can occur when you manually change a parameter, such as node_type, and are reflected in the next maintenance window. Because of this, Terraform may report a difference in its planning phase because a modification has not yet taken place. You can use the apply_immediately flag to instruct the service to apply the change immediately (see documentation below).

~> Note: using apply_immediately can result in a brief downtime as the server reboots. See the AWS Docs on Modifying an ElastiCache Cache Cluster for more information.

Example Usage

resource "aws_elasticache_cluster" "bar" {
    cluster_id = "cluster-example"
    engine = "memcached"
    node_type = "cache.t2.micro"
    port = 11211
    num_cache_nodes = 1
    parameter_group_name = "default.memcached1.4"
}

Argument Reference

The following arguments are supported:

  • cluster_id – (Required) Group identifier. ElastiCache converts this name to lowercase

  • engine – (Required) Name of the cache engine to be used for this cache cluster. Valid values for this parameter are memcached or redis

  • engine_version – (Optional) Version number of the cache engine to be used. See Selecting a Cache Engine and Version in the AWS Documentation center for supported versions

  • maintenance_window – (Optional) 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). The minimum maintenance window is a 60 minute period. Example: sun:05:00-sun:09:00

  • node_type – (Required) The compute and memory capacity of the nodes. See Available Cache Node Types for supported node types

  • num_cache_nodes – (Required) The initial number of cache nodes that the cache cluster will have. For Redis, this value must be 1. For Memcache, this value must be between 1 and 20. If this number is reduced on subsequent runs, the highest numbered nodes will be removed.

  • parameter_group_name – (Required) Name of the parameter group to associate with this cache cluster

  • port – (Required) The port number on which each of the cache nodes will accept connections. For Memcache the default is 11211, and for Redis the default port is 6379.

  • subnet_group_name – (Optional, VPC only) Name of the subnet group to be used for the cache cluster.

  • security_group_names – (Optional, EC2 Classic only) List of security group names to associate with this cache cluster

  • security_group_ids – (Optional, VPC only) One or more VPC security groups associated with the cache cluster

  • apply_immediately - (Optional) Specifies whether any database modifications are applied immediately, or during the next maintenance window. Default is false. See Amazon ElastiCache Documentation for more information. (Available since v0.6.0)

  • snapshot_arns – (Optional) A single-element string list containing an Amazon Resource Name (ARN) of a Redis RDB snapshot file stored in Amazon S3. Example: arn:aws:s3:::my_bucket/snapshot1.rdb

  • snapshot_name - (Optional) The name of a snapshot from which to restore data into the new node group. Changing the snapshot_name forces a new resource.

  • snapshot_window - (Optional, Redis only) The daily time range (in UTC) during which ElastiCache will begin taking a daily snapshot of your cache cluster. Example: 05:00-09:00

  • snapshot_retention_limit - (Optional, Redis only) The number of days for which ElastiCache will retain automatic cache cluster snapshots before deleting them. For example, if you set SnapshotRetentionLimit to 5, then a snapshot that was taken today will be retained for 5 days before being deleted. If the value of SnapshotRetentionLimit is set to zero (0), backups are turned off. Please note that setting a snapshot_retention_limit is not supported on cache.t1.micro or cache.t2.* cache nodes

  • notification_topic_arn – (Optional) An Amazon Resource Name (ARN) of an SNS topic to send ElastiCache notifications to. Example: arn:aws:sns:us-east-1:012345678999:my_sns_topic

  • az_mode - (Optional, Memcached only) Specifies 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. If you want to choose cross-az, num_cache_nodes must be greater than 1

  • availability_zone - (Optional) The Availability Zone for the cache cluster. If you want to create cache nodes in multi-az, use availability_zones

  • availability_zones - (Optional, Memcached only) List of Availability Zones in which the cache nodes will be created. If you want to create cache nodes in single-az, use availability_zone

  • tags - (Optional) A mapping of tags to assign to the resource

~> NOTE: Snapshotting functionality is not compatible with t2 instance types.

Attributes Reference

The following attributes are exported:

  • cache_nodes - List of node objects including id, address, port and availability_zone. Referenceable e.g. as ${aws_elasticache_cluster.bar.cache_nodes.0.address}

  • configuration_endpoint - (Memcached only) The configuration endpoint to allow host discovery