# NATS


Zerops provides a fully managed [NATS](https://nats.io/) messaging system with automated scaling and zero infrastructure overhead, letting developers focus entirely on development.

## Supported Versions

Currently supported NATS version:

Import configuration version:

## Service Configuration

Our NATS implementation features optimized default settings designed for common use cases.

**Key configuration aspects** include:
- Standard protocol port `4222` for client connections
- HTTP monitoring interface `8222` for management
- Secure authentication with automatically generated credentials
- Optimized settings for performance and reliability

You can fine-tune your NATS service by adjusting **environment variables**:

### Available Configuration Options

:::note
If certain variables are not visible in your configuration, they may have been introduced after your service was created. Simply add them as [secret variables](/features/env-variables#2-secret-variables) to access the functionality.
:::

<table className="w-full my-1.5">
  <thead>
    <tr>
      <th className="w-fit">Variable</th>
      <th className="w-fit">Description</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td className="w-fit whitespace-nowrap"><code>MAX_PAYLOAD</code></td>
      <td className="w-fit">Defines the maximum allowed message size for all NATS traffic. Default: <code>8MB</code>, Maximum: <code>64MB</code>. See [NATS limits documentation](https://docs.nats.io/running-a-nats-service/configuration#limits) for details.</td>
    </tr>
    <tr>
      <td className="w-fit whitespace-nowrap"><code>JET_STREAM_ENABLED</code></td>
      <td className="w-fit">Controls whether JetStream functionality is enabled. Default: <code>1</code> (enabled), Set to <code>0</code> to disable. See [JetStream Configuration](#jetstream-configuration) section below for more details.</td>
    </tr>
  </tbody>
</table>

:::important
Configuration changes require a service **restart** to take effect. While NATS itself supports configuration hot-reload, this feature will be implemented in a future Zerops update.
:::

After restarting, check your service logs to confirm the changes were applied successfully.

### JetStream Configuration

The service includes [JetStream](https://docs.nats.io/nats-concepts/jetstream) functionality **enabled by default**, providing persistent storage capabilities for your messaging workloads:
- **Memory store**: Up to 40GB for high-performance message caching
- **File store**: Up to 250GB for persistent storage
- **Regular sync intervals**: Ensures data durability and consistency

:::note
In HA deployments, data persistence is further enhanced with 1-minute sync intervals across all nodes, ensuring robust data durability and high availability.
:::

This configuration provides a robust foundation for message persistence while balancing performance and reliability.

:::tip
Disabling JetStream can reduce resource utilization for applications that don't require message persistence.
:::

### Deployment Modes

:::warning
Deployment mode is selected during service creation and cannot be changed later.
:::

#### Non-HA Mode
- Suitable for development and testing
- Data persistence not guaranteed during node failures
- Lower resource requirements

#### HA Mode
- Creates a multi-node NATS cluster
- Configures routes between cluster nodes automatically
- Implements [NATS clustering](https://docs.nats.io/running-a-nats-service/configuration/clustering) for high availability
- Provides improved reliability compared to non-HA deployments

### Authentication Management

Authentication credentials are automatically generated and managed by the platform. The system creates a default user (`zerops`) with a secure 16-character password. You can access these credentials through:
- The service access details in the Zerops GUI
- Environment variables in your service configuration:
  - `user` - Username for authentication (default: "zerops")
  - `password` - Generated secure password
  - `connectionString` - Complete connection string in the format `nats://:@:`

## Health Monitoring

Zerops continuously monitors your NATS service health using built-in health checks:

- **HTTP Health Check**: The system checks the `/healthz` endpoint at port 8222
- **Self-Healing**: The platform automatically recovers unhealthy nodes when issues are detected

### Health Status

You can check the health status of your NATS service:

1. Through the Zerops GUI dashboard
2. By accessing the management interface at port `8222`

## Backup and Recovery

NATS backups are created using filesystem archival:

- **Format**: `.tar.gz` (archive of queue state)
- **Tooling**: Filesystem archival
- **Content**: Captures persistent message state

For backup configuration, scheduling, retention policies, and management options, see the [Zerops Backups](/features/backup) documentation.

### Restoring Backups

To restore a NATS backup:

1. **Download** the backup file (`.tar.gz`) from the Zerops UI
2. **Extract** the archive to access the queue state data
3. **Prepare** your target environment (clear existing data if needed)
4. **Restore** using NATS CLI commands via Zerops VPN or during deployment. Follow the [official NATS documentation](https://docs.nats.io/running-a-nats-service/nats_admin/jetstream_admin/disaster_recovery) for detailed restore procedures.

For assistance with the restoration process, contact Zerops support.

## Support

For advanced configurations or custom requirements:
- Join our [Discord community](https://discord.gg/zerops)
- Contact support via [email](mailto:support@zerops.io)