# Terraform — simulation environment (T4)

Declares the simulated fleet and its observability stack on the k3d cluster
created by [`../../ansible/sim-cluster.yml`](../../ansible/sim-cluster.yml).
This module is the executable miniature of the dev/sim environment from
[06 — Environments](../../../docs/06-environments.md).

| Resource | Purpose |
| --- | --- |
| StatefulSet `drone` × `drone_count` | Virtual drones; stable pod names become `DRONE_ID`s; all write Hive-partitioned Parquet into the shared `/data` lake |
| Deployment `exporter` | Prometheus exporter reading the lake with DuckDB |
| Deployment `explorer` + NodePort 30088 | Partition tree + read-only SQL console (also feeds the prototype's live mode) |
| Deployment `prometheus` + NodePort 30990 | Scrapes the exporter |
| Deployment `grafana` + NodePort 30300 | Same dashboard JSON as the Compose profile, provisioned from a ConfigMap |

## Usage

```bash
ansible-playbook ../../ansible/sim-cluster.yml   # once: cluster + image
terraform init
terraform apply
terraform output                                  # URLs
```

Scale the fleet without touching YAML:

```bash
terraform apply -var drone_count=9 -var speedup=4
```

## Notes

- `image_pull_policy = "Never"` — the simulator image is imported by the
  Ansible playbook (`k3d image import`); the cluster never pulls from a
  registry, mirroring the air-gap doctrine.
- Pods discover their identity from the pod name (StatefulSet ordinal), so
  a flight survives `kubectl delete pod` the same way a drone survives a
  power cycle: new process, same identity, new flight ID.
- State is local (`terraform.tfstate` in this directory) — the simulation
  cluster is disposable; nothing here is shared infrastructure.