---
title: "discovery.dns | Grafana Alloy documentation"
description: "Learn about discovery.dns"
---

# `discovery.dns`

`discovery.dns` discovers scrape targets from DNS records.

## Usage

Alloy ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```alloy
discovery.dns "<LABEL>" {
  names = ["<NAME_1>", "<NAME_2>", ...]
}
```

## Arguments

You can use the following arguments with `discovery.dns`:

Expand table

| Name               | Type           | Description                                                          | Default | Required |
|--------------------|----------------|----------------------------------------------------------------------|---------|----------|
| `names`            | `list(string)` | DNS names to look up.                                                |         | yes      |
| `port`             | `number`       | Port to use for collecting metrics. Not used for SRV records.        | `0`     | no       |
| `refresh_interval` | `duration`     | How often to query DNS for updates.                                  | `"30s"` | no       |
| `type`             | `string`       | Type of DNS record to query. Must be one of SRV, A, AAAA, MX, or NS. | `"SRV"` | no       |

## Blocks

The `discovery.dns` component doesn’t support any blocks. You can configure this component with arguments.

## Exported fields

The following field is exported and can be referenced by other components:

Expand table

| Name      | Type                | Description                                         |
|-----------|---------------------|-----------------------------------------------------|
| `targets` | `list(map(string))` | The set of targets discovered from the DNS records. |

Each target includes the following labels:

- `__meta_dns_mx_record_target`: Target field of the MX record.
- `__meta_dns_name`: Name of the record that produced the discovered target.
- `__meta_dns_ns_record_target`: Target field of the NS record.
- `__meta_dns_srv_record_port`: Port field of the SRV record.
- `__meta_dns_srv_record_target`: Target field of the SRV record.

## Component health

`discovery.dns` is only reported as unhealthy when given an invalid configuration. In those cases, exported fields retain their last healthy values.

## Debug information

`discovery.dns` doesn’t expose any component-specific debug information.

## Debug metrics

`discovery.dns` doesn’t expose any component-specific debug metrics.

## Example

This example discovers targets from an A record.

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```alloy
discovery.dns "dns_lookup" {
  names = ["myservice.example.com", "myotherservice.example.com"]
  type = "A"
  port = 8080
}

prometheus.scrape "demo" {
  targets    = discovery.dns.dns_lookup.targets
  forward_to = [prometheus.remote_write.demo.receiver]
}

prometheus.remote_write "demo" {
  endpoint {
    url = "<PROMETHEUS_REMOTE_WRITE_URL>"

    basic_auth {
      username = "<USERNAME>"
      password = "<PASSWORD>"
    }
  }
}
```

Replace the following:

- *`<PROMETHEUS_REMOTE_WRITE_URL>`* : The URL of the Prometheus remote\_write-compatible server to send metrics to.
- *`<USERNAME>`* : The username to use for authentication to the `remote_write` API.
- *`<PASSWORD>`* : The password to use for authentication to the `remote_write` API.

## Compatible components

`discovery.dns` has exports that can be consumed by the following components:

- Components that consume [Targets](../../../compatibility/#targets-consumers)

> Note
> 
> Connecting some components may not be sensible or components may require further configuration to make the connection work correctly. Refer to the linked documentation for more details.