# Prometheus Agent Remote Write Config

## Using an Existing Prometheus Server

1. Determine the ingress IP for the Kloudfuse stack.

```
kubectl get svc | grep kfuse-ingress-nginx-controller
```

You can use either the EXTERNAL-IP address, or DNS name.

|     |     |
| --- | --- |
|  | DNS name does not work if the Kloudfuse stack is on a different VPC or cluster than the target cluster.<br>You can use the IP address in all circumstances. |

2. Add a `remote_write` endpoint to use the Prometheus server. Choose the correct option, depending on your network protocol (`http` or `https`):

```
http://<REPLACE KFUSE ADDRESS>/write as the remote_write

https://<REPLACE KFUSE ADDRESS>/write as the remote_write
```

|     |     |
| --- | --- |
|  | Starting with Kloudfuse 3.4.3 and Prometheus 2.40+, native histograms are supported. To enable sending native histograms, add `send_native_histograms: true` to your remote write configuration. See [Native and Exponential Histograms](https://docs.kloudfuse.com/platform/4.0.2/signals/metrics/histogram-native-exponential/) for more details. |

3. If the Prometheus server is installed using the standalone [Prometheus helm chart](https://github.com/prometheus-community/helm-charts/tree/main/charts/prometheus), add the following `helm` values and run `helm upgrade`:

```
server:
     # For Prometheus 2.40+ and Kloudfuse 3.4.3+, enable native histograms feature:
     extraArgs:
       enable-feature: native-histograms

serverFiles:
     prometheus.yml:
       remote_write:
      - url: http://<REPLACE KFUSE ADDRESS>/write
        queue_config:
          max_samples_per_send: 4000
        # For Prometheus 2.40+ and Kloudfuse 3.4.3+, enable native histograms:
        send_native_histograms: true
```

## Prometheus Operator

### Helm Chart Values

Use these steps if the Prometheus server is installed using Prometheus Operator or [kube-prometheus-stack helm chart](https://github.com/prometheus-community/helm-charts/tree/main/charts/kube-prometheus-stack):

1. Add the following helm values:

```
prometheus:
     prometheusSpec:
       # For Prometheus 2.40+ and Kloudfuse 3.4.3+, enable native histograms feature:
       enableFeatures:
      - native-histograms
remoteWrite:
    - queueConfig:
        maxSamplesPerSend: 4000
      url: http://<REPLACE KFUSE ADDRESS>/write
      # For Prometheus 2.40+ and Kloudfuse 3.4.3+, enable native histograms:
      sendNativeHistograms: true
```

2. Run `helm upgrade`.

### Prometheus CRD

Alternatively, configure the remote write through Prometheus CRD.

Update the Prometheus CRD (kind: Prometheus) using the following configuration:

```
# For Prometheus 2.40+ and Kloudfuse 3.4.3+, enable native histograms feature:
enableFeatures:
  - native-histograms

remoteWrite:
  - queueConfig:
      maxSamplesPerSend: 4000
    url: http://<REPLACE KFUSE ADDRESS>/write
    # For Prometheus 2.40+ and Kloudfuse 3.4.3+, enable native histograms:
    sendNativeHistograms: true
```

## Replacing the Prometheus Server

You can also replace the Prometheus server with Grafana Agent, which is lighter-weight and can be configured to scrape and emit write metrics.

Use the following helm chart to install the agent. Use the following helm values:

```
config:
  prometheus:
    remoteWrite:
      url: http://<REPLACE KfUSE ADDRESS>/write
    configs:
      <copy existing scrape configs here>
```