# Cortex Integration

[Cortex](https://cortexmetrics.io/) is a [CNCF](https://cncf.io) incubation project used in several production systems including [Amazon Managed Service for Prometheus (AMP)](https://aws.amazon.com/prometheus/) and it provides horizontally scalable, highly available, multi-tenant, long term storage for [Prometheus](https://prometheus.io/).

{% hint style="info" %}
You can use our [example prometheus setup](https://github.com/iLert/prometheus-integration-docs) to test the Cortex integration
{% endhint %}

## In ilert <a href="#create-alert-source" id="create-alert-source"></a>

## Create a Cortex alert source <a href="#create-alert-source" id="create-alert-source"></a>

1. Go to **Alert sources** -> **Alert sources** and click on **Create new alert source**<br>

<figure><img src="/files/rmL9OoRxcWnDwcJZQm4Y" alt=""><figcaption></figcaption></figure>

1. Search for **Cortex** in the search field, click on the Cortex tile, and click on **Next**.<br>

   <figure><img src="/files/1WoRRYB5U40PbeMJ7Hit" alt=""><figcaption></figcaption></figure>
2. Give your alert source a name, optionally assign teams, and click **Next**.
3. Select an **escalation policy** by creating a new one or assigning an existing one.<br>

   <figure><img src="/files/y4Bakf2apGhBN56U8ZPR" alt=""><figcaption></figcaption></figure>
4. Select your [Alert grouping](/alerting/configure-alerting/alert-sources.md#alert-grouping) preference and click **Continue setup**. You may click **Do not group alerts** for now and change it later.<br>

   <figure><img src="/files/nTlB0ZCIW1SP3dj6P9nO" alt=""><figcaption></figcaption></figure>
5. The next page shows additional settings such as customer alert templates or notification prioritiy. Click on **Finish setup** for now.
6. On the final page, a Cortex URL will be generated that you will need later in this guide.

<figure><img src="/files/ru7g3ky2gEwrnOSAyaIx" alt=""><figcaption></figcaption></figure>

## In Prometheus Alertmanager <a href="#create-alert-source" id="create-alert-source"></a>

> In order to be able to use cortex alerts and receive notifications, you need first configure and start alertmanager

1. Install Prometheus Alertmanager in any way that suits your needs. For more information about the alertmanager installation process please visit <https://prometheus.io/docs/alerting/latest/alertmanager/>
2. Configure Alertmanager receivers in order to inform ilert every time there's an alert. In the example below replace the previously created Cortex URL:

{% code title="alertmanager.yaml" lineNumbers="true" %}

```yaml
receivers:
  - name: "ilert"
    webhook_configs:
      - url: "<your alert source url here>"
        send_resolved: true
```

{% endcode %}

{% hint style="info" %}
You could also split alert to high and low priority by creating two alert sources accordingly
{% endhint %}

<pre class="language-yaml" data-title="alertmanager.yaml" data-line-numbers><code class="lang-yaml"><strong>receivers:
</strong>  - name: "high-priority"
    webhook_configs:
      # high priority alert source url
      - url: "&#x3C;your high priority alert source url here>"
        send_resolved: true
  - name: "low-priority"
    webhook_configs:
      # low priority alert source url
      - url: "&#x3C;your low priority alert source url here>"
        send_resolved: true
</code></pre>

## In Cortex <a href="#create-alert-source" id="create-alert-source"></a>

1. Install Cortex in any way that suits your needs.
2. Configure the Cortex alert rules in order to trigger alerts regarding the rule expression. For example:

{% code title="cortex-alert-rules.yaml" lineNumbers="true" %}

```yaml
groups:
  - name: cortex-critical
    rules:
      - alert: PrometheusDown
        expr: sum(up{instance=~"prometheus.*"}) < 1
        for: 15s
        labels:
          severity: critical
        annotations:
          summary: Prometheus is down alert
          description: "Prometheus is down \n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
```

{% endcode %}

3. Configure the Mimir ruler to send alerts to an external alertmanager and point the alert rules folder:

{% code title="cortex-config.yaml" lineNumbers="true" %}

```yaml
ruler:
  alertmanager_url: http://alertmanager:9093
  enable_api: true

ruler_storage:
  backend: local
  local:
    directory: /etc/alertmanager
```

{% endcode %}

## FAQ

**Will alerts in ilert be resolved automatically?**

Yes, as soon as the Alertmanager sends a "RESOLVE" event, the associated alert is automatically resolved in ilert.


---

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