OpenSearch — Amazon OpenSearch Service
Quick start, the domain and tag operations that work, and why the domain endpoint answers nothing: no cluster, no cluster settings, no configuration changes.
Domains are control-plane records only: no search cluster is started, so
DomainStatus.Endpoint names a host that answers nothing.
Status: ⚠️ Partial
Quick start
export AWS_ENDPOINT_URL=http://localhost:4566
aws opensearch create-domain \
--domain-name logs \
--engine-version OpenSearch_2.11
aws opensearch describe-domain --domain-name logs
aws opensearch list-domain-namesAny credentials work; with none configured, run eval "$(overcast env)" first
— see Using AWS SDKs and CLI.
What works
| Area | Behaviour |
|---|---|
| Domains | Create, describe, batch-describe, list and delete; active the moment they are created |
| Name collisions | A repeat domain name in the same region is rejected |
| Input validation | DomainName (3-28 characters of [a-z][a-z0-9-]) and EngineVersion (OpenSearch_X.Y or Elasticsearch_X.Y) are checked, as AWS checks them |
| Regions | Domains are per-region — the same name in two regions is two domains |
| Filtering | ListDomainNames --engine-type is honoured, derived from each domain’s EngineVersion |
| Tags | Inline TagList at creation, plus AddTags, ListTags and RemoveTags; deleting a domain deletes its tags |
Differences from AWS
| Area | On AWS | Overcast |
|---|---|---|
| The cluster | Indexes documents and serves queries | Nothing is indexed or queried; the domain endpoint is a name, not a service |
DomainStatus | The full shape | The four required members plus EngineVersion, Endpoint and the Created/Deleted/Processing flags; the rest is omitted |
| Cluster settings | Configure the cluster | ClusterConfig is echoed back unchanged; EBSOptions, VPCOptions, access policies and the other ~25 CreateDomain members are accepted and ignored |
Endpoint | A live domain host on port 443 | An AWS-shaped hostname that nothing answers on |
| Configuration changes | UpdateDomainConfig, upgrades, package association and auto-tune | Not implemented |
| Cross-cluster search | Outbound and inbound connections | Not modelled |
Gotchas
Warning
Client libraries that talk the OpenSearch REST API (index, search, bulk) address the domain endpoint directly, not this control plane. Those calls reach nothing here — run a real OpenSearch container alongside Overcast if your test needs to index documents.
DomainStatus.Endpoint is a bare hostname, the way AWS reports one, and a
domain’s data plane lives on that host rather than on a path beneath the
control-plane endpoint. There is no prefix to point a search client at: the
management operations above are the whole of what Overcast serves.
Operations
All 8 listed operations are implemented. Per-operation status, notes and AWS API links: OpenSearch operations.