---
page_title: "ona_warm_pool Resource - ona"
subcategory: "Projects"
description: |-
  Ona warm pool. A warm pool keeps pre-created environments available for one project and environment class. The project must have prebuilds enabled for the environment class before the warm pool can be created.
---

# ona_warm_pool (Resource)

Ona warm pool. A warm pool keeps pre-created environments available for one project and environment class. The project must have prebuilds enabled for the environment class before the warm pool can be created.

For product context, see [Warm Pools](https://ona.com/docs/ona/projects/warm-pools) and [Prebuilds](https://ona.com/docs/ona/projects/prebuilds).

## Example Usage

```terraform
resource "ona_project" "api" {
  name                 = "acme-api"
  repository_clone_url = "https://github.com/acme/api.git"
  branch               = "main"

  environment_class {
    environment_class_id = ona_environment_class.large.id
    order                = 0
  }

  prebuild_configuration {
    enabled               = true
    environment_class_ids = [ona_environment_class.large.id]
    timeout               = "1h"

    daily_schedule {
      hour_utc = 5
    }
  }
}

resource "ona_warm_pool" "api_large" {
  project_id           = ona_project.api.id
  environment_class_id = ona_environment_class.large.id
  min_size             = 0
  max_size             = 5
}
```

<!-- schema generated by tfplugindocs -->
## Schema

### Required

- `environment_class_id` (String) Environment class ID whose instances are warmed.
- `project_id` (String) Project ID this warm pool belongs to.

### Optional

- `max_size` (Number) Maximum number of warm instances to maintain. Must be between 1 and 20 and no smaller than `min_size`.
- `min_size` (Number) Minimum number of warm instances to maintain. Must be between 0 and 20 and no larger than `max_size`.

### Read-Only

- `created_at` (String) Time when the warm pool was created.
- `id` (String) Warm pool ID. Use this value as the Terraform import ID.

## Import

Import is supported using the following syntax:

The [`terraform import` command](https://developer.hashicorp.com/terraform/cli/commands/import) can be used, for example:

```shell
#!/usr/bin/env sh

terraform import ona_warm_pool.api_large 00000000-0000-0000-0000-000000000000
```