# Create an alert manager configuration in Amazon Managed Service for Prometheus to manage and route alerts
<a name="AMP-alertmanager-config"></a>

To use alert manager and templating in Amazon Managed Service for Prometheus, you create an alert manager configuration YAML file. An Amazon Managed Service for Prometheus alert manager file has two main sections:
+ `template_files:` contains the templates used for messages sent by receivers. For more information, see [Template Reference](https://prometheus.io/docs/prometheus/latest/configuration/template_reference/) and [Template Examples](https://prometheus.io/docs/prometheus/latest/configuration/template_examples/) in the Prometheus documentation.
+ `alertmanager_config:` contains the alert manager configuration. This uses the same structure as an alert manager config file in standalone Prometheus. For more information, see [Configuration](https://prometheus.io/docs/alerting/latest/configuration/) in the Alertmanager documentation.
**Note**  
The `repeat_interval` configuration described in the Prometheus documentation above has an additional limitation in Amazon Managed Service for Prometheus. The maximum allowed value is five days. If you set it higher than five days, it will be treated as five days and notifications will be sent again after the five day period has passed.

**Note**  
You can also edit the configuration file directly in the Amazon Managed Service for Prometheus console, but it must still follow the format specified here. For more information on uploading or editing a configuration file, see [Upload your alert manager configuration file to Amazon Managed Service for Prometheus](AMP-alertmanager-upload.md).

In Amazon Managed Service for Prometheus, your alert manager configuration file must have all your alert manager configuration content inside of an `alertmanager_config` key at the root of the YAML file.

The following is a basic example alert manager configuration file:

```
alertmanager_config: |
  route:
    receiver: 'default'
  receivers:
    - name: 'default'
      sns_configs:
      - topic_arn: arn:aws:sns:us-east-2:123456789012:My-Topic
        sigv4:
          region: us-east-2
        attributes:
          key: key1
          value: value1
```

The only receiver currently supported is Amazon Simple Notification Service (Amazon SNS). If you have other types of receivers listed in the configuration, it will be rejected.

Here is another sample alert manager configuration file that uses both the `template_files` block and the `alertmanager_config` block.

```
template_files:
  default_template: |
    {{ define "sns.default.subject" }}[{{ .Status | toUpper }}{{ if eq .Status "firing" }}:{{ .Alerts.Firing | len }}{{ end }}]{{ end }}
    {{ define "__alertmanager" }}AlertManager{{ end }}
    {{ define "__alertmanagerURL" }}{{ .ExternalURL }}/#/alerts?receiver={{ .Receiver | urlquery }}{{ end }}
alertmanager_config: |
  global:
  templates:
    - 'default_template'
  route:
    receiver: default
  receivers:
    - name: 'default'
      sns_configs:
      - topic_arn: arn:aws:sns:us-east-2:accountid:My-Topic
        sigv4:
          region: us-east-2
        attributes:
          key: severity
          value: SEV2
```

**Default Amazon SNS template block**

The default Amazon SNS configuration uses the following template unless you explicitly override it.

```
{{ define "sns.default.message" }}{{ .CommonAnnotations.SortedPairs.Values | join " " }}
  {{ if gt (len .Alerts.Firing) 0 -}}
  Alerts Firing:
    {{ template "__text_alert_list" .Alerts.Firing }}
  {{- end }} 
  {{ if gt (len .Alerts.Resolved) 0 -}} 
  Alerts Resolved:
    {{ template "__text_alert_list" .Alerts.Resolved }}
  {{- end }}
{{- end }}
```