Neptune DB clusters should be deployed across multiple Availability Zones

How to fix it

• Affects another check: RDS.15 also reports this cluster until it has instances in two zones, so the new reader clears that finding too.

In the console

Neptune → Databases → the DB cluster → Actions → Add reader

Availability zone

A different zone from the primary instance's (only zones in the cluster's DB subnet group are listed)

DB instance class

The same class as the primary, so the reader can carry the load once promoted

With the AWS CLI

aws neptune create-db-instance --db-instance-identifier <new-reader-identifier> --db-cluster-identifier <db-cluster-identifier> --db-instance-class <db-instance-class> --engine neptune --availability-zone <availability-zone> --region <region>

With Terraform

resource "aws_neptune_cluster_instance" "reader" {
  cluster_identifier = var.cluster_identifier
  instance_class     = var.instance_class
  availability_zone  = var.reader_availability_zone
}