+++
title = "KEDA Metrics Server"
description = "Details on KEDA Metrics Server"
weight = 100
+++

## Querying metrics exposed by KEDA Metrics Server

The metrics exposed by KEDA Metrics Server can be queried directly using `kubectl`:
```bash
kubectl get --raw "/apis/external.metrics.k8s.io/v1beta1"
```

This will return a json with the list of metrics exposed by KEDA:
```json
{
  "kind": "APIResourceList",
  "apiVersion": "v1",
  "groupVersion": "external.metrics.k8s.io/v1beta1",
  "resources": [
    {
      "name": "s0-rabbitmq-queueName",
      "singularName": "",
      "namespaced": true,
      "kind": "ExternalMetricValueList",
      "verbs": [
        "get"
      ]
    },
    {
      "name": "s1-rabbitmq-queueName2",
      ....
    }
  ]
}
```

You can also query for the value of a specific metric using `kubectl`:
```bash
kubectl get --raw "/apis/external.metrics.k8s.io/v1beta1/namespaces/YOUR_NAMESPACE/YOUR_METRIC_NAME"
```

At this point, you should take in consideration that KEDA metrics are namespaced, this means that you have to specify the namespace where the `ScaledObject` is placed inside.

For example, if you want to get the value of the metric named `s1-rabbitmq-queueName2` in namespace `sample-ns`, the query will be like this:
```bash
kubectl get --raw "/apis/external.metrics.k8s.io/v1beta1/namespaces/sample-ns/s1-rabbitmq-queueName2"
```

And it will show a json like this:

```json
{
  "kind": "ExternalMetricValueList",
  "apiVersion": "external.metrics.k8s.io/v1beta1",
  "metadata": {},
  "items": [
    {
      "metricName": "s1-rabbitmq-queueName2",
      "metricLabels": null,
      "timestamp": "2021-10-20T10:48:17Z",
      "value": "0"
    }
  ]
}
```

> **Note:** There are 2 exceptions in querying metrics and those are `cpu` and `memory` scalers. When KEDA creates the HPA object, it uses standard `cpu` and `memory` metrics from the Kubernetes Metrics Server. If you want to query these 2 specific values, you should do it using `/apis/metrics.k8s.io/v1beta1` instead of `/apis/external.metrics.k8s.io/v1beta1`.

## How to get metric names from ScaledObject

During its work, KEDA updates each ScaledObject with some relevant information which it needs to work. Part of that information is metric names generated from the triggers inside the own ScaledObject.

You can recover the metric names from a ScaledObject using `kubectl`:
```bash
 kubectl get scaledobject SCALEDOBJECT_NAME -n NAMESPACE -o jsonpath={.status.externalMetricNames}
```

## How to get metric when multiple ScaledObjects have the same metric name

KEDA will try to select the proper `ScaledObject` for your metric and there should only be one. In case of having multiple `ScaledObject`s in the same namespace with the same metric name, an error like this will be thrown:

```
Error from server: exactly one ScaledObject should match label
```

In this case, you should add in the query string the `labelSelector` to match the proper `ScaledObject` (in url format). The needed selector is `scaledobject.keda.sh/name: {ScaledObjectName}`. You can achieve this as following:

```bash
 kubectl get scaledobject SCALEDOBJECT_NAME -n NAMESPACE -o jsonpath={.metadata.labels}
```

Once you have the selector, you have to add it to your query string as following:

```bash
kubectl get --raw "/apis/external.metrics.k8s.io/v1beta1/namespaces/sample-ns/s1-rabbitmq-queueName2?labelSelector=scaledobject.keda.sh%2Fname%3D{ScaledObjectName}"
```