How to Import an AWS ElastiCache Cluster into Terraform

Import AWS ElastiCache Cluster with Terraback (recommended)

Terraback reverse-engineers your live infrastructure: it reads the Amazon ElastiCache resource with read-only credentials, generates the HCL, and produces the exact import block. Two commands take you from a live AWS ElastiCache Cluster to managed Terraform.

terraback scan all aws --region us-east-1

terraback aws import --method bulk

The Terraform import block

Terraback emits a Terraform 1.5+ import block like the one below. Because the block lives in your configuration, the import is reviewable in a pull request and repeatable across environments.

import {
  to = aws_elasticache_cluster.prod
  id = "prod-redis"
}

Example aws_elasticache_cluster configuration

Here is a realistic AWS ElastiCache Cluster block. Terraback generates a fuller version from your actual resource attributes; this is a minimal, valid starting point.

resource "aws_elasticache_cluster" "prod" {
  cluster_id           = "prod-redis"
  engine               = "redis"
  node_type            = "cache.t3.micro"
  num_cache_nodes      = 1
  engine_version       = "7.1"
  port                 = 6379
  subnet_group_name    = "prod-cache-subnets"
}

Gotchas when importing a AWS ElastiCache Cluster

• Import by the cluster_id, not by ARN.
• A cluster that is a member of a replication group must be managed through aws_elasticache_replication_group, not imported as a standalone aws_elasticache_cluster.
• The subnet group, parameter group, and security groups are separate resources and are not imported with the cluster.
• Memcached supports num_cache_nodes greater than one; Redis (non-cluster mode) is always a single node, so reconcile the engine and node count carefully.

Doing it manually with terraform import

The native approach is to write the aws_elasticache_cluster block by hand, then run terraform import aws_elasticache_cluster.example <import-id> for every resource, one at a time. That works for a handful of resources, but it does not scale: you author all the HCL yourself and repeat the command for each item. Terraback generates the HCL and the import blocks for your whole account in one pass.

Import other AWS resources