> For the complete documentation index, see [llms.txt](https://docs.ilert.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ilert.com/integrations/inbound-integrations/cortex.md).
# Cortex Integration
Connect Cortex Metrics with ilert to route performance and observability alerts to on-call responders and escalate issues from Prometheus-based systems.
[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
## Create a Cortex alert source
1. Go to **Alerting** → **Alert sources** and click **Create new alert source**.
2. Search for **Cortex**, click its tile, and click **Next**.
3. Give your alert source a name, optionally assign teams, and click **Next**.
4. Choose who gets notified: select **Use existing escalation policy** and pick a policy, or **Generate new escalation policy** to start with a basic one that notifies you first. Click **Next**.
Pick an existing escalation policy, or generate a basic one without leaving the wizard.
5. Select **Default grouping** and click **Continue setup**. It groups events by the alert key the integration sets; the other [grouping options](/alerting/configure-alerting/alert-sources.md#event-grouping) are easier to judge once events are arriving.
6. The next page shows more settings, such as notification priority and alert templates. Click **Finish setup** for now; you can change them later.
7. On the final page, a Cortex URL will be generated that you will need later in this guide.
## In Prometheus Alertmanager
> 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
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: ""
send_resolved: true
```
{% endcode %}
{% hint style="info" %}
You could also split alert to high and low priority by creating two alert sources accordingly
{% endhint %}
## In Cortex
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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