> ## Documentation Index
> Fetch the complete documentation index at: https://docs.techulus.cloud/llms.txt
> Use this file to discover all available pages before exploring further.

# Registry

> Private container image registry.

Techulus Cloud runs a private [Docker Distribution Registry](https://distribution.github.io/distribution/) for storing container images built from source.

## How It Works

When you deploy from a GitHub repository, an agent builds the container image using BuildKit and pushes it to the registry. Other agents pull the image from the registry during deployment.

Images are tagged with the commit SHA:

```
registry.example.com/{project_id}/{service_id}:{commit_sha}
```

## Configuration

The registry runs as a Docker container alongside the control plane, available at `https://registry.<ROOT_DOMAIN>`.

| Variable               | Description                  |
| ---------------------- | ---------------------------- |
| `REGISTRY_USERNAME`    | Basic auth username          |
| `REGISTRY_PASSWORD`    | Basic auth password          |
| `REGISTRY_HTTP_SECRET` | Internal HTTP signing secret |

Agents receive registry credentials automatically during [registration](/agents/setup#registration).

## Storage

Images are stored on the local filesystem in a persistent Docker volume (`registry-data`). Delete operations are enabled for garbage collection.

### Garbage Collection

To reclaim disk space from deleted images, run garbage collection manually:

```bash theme={null}
docker exec registry /bin/registry garbage-collect /etc/docker/registry/config.yml
```

For automatic cleanup, add a daily cron job:

```bash theme={null}
0 2 * * * docker exec registry /bin/registry garbage-collect /etc/docker/registry/config.yml
```