OpenSearch / Elasticsearch domain runs on a single instance

What it checks

OpenSearch: one data node is configured.

Where it applies

Terraform: aws_opensearch_domain, aws_elasticsearch_domain

CloudFormation: AWS::OpenSearchService::Domain, AWS::Elasticsearch::Domain

How to fix it

1. Use at least 3 data nodes, or 3 dedicated masters plus at least 2 data nodes; masters do not hold data. Terraform: set cluster_config.instance_count >= 3, or dedicated_master_enabled = true and dedicated_master_count = 3 with instance_count >= 2. CloudFormation: use InstanceCount >= 3, or DedicatedMasterEnabled = true and DedicatedMasterCount = 3 with InstanceCount >= 2, under ClusterConfig for OpenSearch or ElasticsearchClusterConfig for Elasticsearch. Enable zone awareness using an Availability Zone count supported by the chosen data-node count and deployment mode; use two Availability Zones for a two-data-node deployment.

Frameworks

• AWS Well-Architected REL.7

These mappings are advisory, not an attestation of compliance.

Vendor documentation

All rules