How to Import an AWS ElastiCache Replication Group into Terraform

Import AWS ElastiCache Replication Group 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 Replication Group 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_replication_group.prod
  id = "prod-redis-rg"
}

Example aws_elasticache_replication_group configuration

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

resource "aws_elasticache_replication_group" "prod" {
  replication_group_id = "prod-redis-rg"
  description          = "Production Redis"
  node_type            = "cache.r6g.large"
  engine               = "redis"
  engine_version       = "7.1"
  port                 = 6379
  num_cache_clusters   = 2
  subnet_group_name    = "prod-cache-subnets"
}

Gotchas when importing a AWS ElastiCache Replication Group

• Import by the replication_group_id, not by ARN.
• The auth_token (Redis AUTH password) is never returned by AWS; supply it via a variable or it will show a diff.
• Member clusters are managed implicitly by the replication group; do not also import them as aws_elasticache_cluster resources.
• Switching between num_cache_clusters and the cluster-mode num_node_groups/replicas_per_node_group style can force replacement; match the live topology.

Doing it manually with terraform import

The native approach is to write the aws_elasticache_replication_group block by hand, then run terraform import aws_elasticache_replication_group.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