ElastiCache ClusterMode Error in terraform-provider-aws 3.26.0

ToC

Just a memo.

With terraform-provider-aws 3.26.0, the following configuration results in an error.

resource "aws_elasticache_replication_group" "cache_store" {
  automatic_failover_enabled    = true

  # NOTE: 商用環境以外でコストを抑えるべく必要最低限のリソースの起動にする
  cluster_mode {
    replicas_per_node_group = 0
    num_node_groups         = 1
  }
  ...
}

Error: if automatic_failover_enabled is true, number_cache_clusters must be greater than 1

  on redis_cache.tf line 12, in resource "aws_elasticache_replication_group" "cache_store":
  12: resource "aws_elasticache_replication_group" "cache_store" {

You need to fix it as follows.

resource "aws_elasticache_replication_group" "cache_store" {
-  automatic_failover_enabled    = true
+  automatic_failover_enabled    = false
  cluster_mode {
    replicas_per_node_group = 0
    num_node_groups         = 1
  }
  ...
}

That’s all.