---
title: Charmhub | Deploy Grafana Agent using Charmhub - The Open Operator Collection
description: Deploy the latest version of Grafana Agent as a Kubernetes Operator on
  any cloud.
url: https://charmhub.io/grafana-agent-k8s/docs/drop-metrics
---

# Grafana Agent

[Canonical Observability](https://charmhub.io/publisher/observability "View all packages from Canonical Observability")

* [Canonical Observability](https://charmhub.io/publisher/observability "View all packages from Canonical Observability")

Platform:

0.40/stable rev229

```
juju deploy grafana-agent-k8s --channel 0.40/stable
```

[Learn to deploy on juju >](https://juju.is/docs/juju/manage-applications)

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#### Relevant links

* [Homepage](https://charmhub.io/grafana-agent-k8s)

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#### Contacts

* [Submit a bug](https://github.com/canonical/grafana-agent-k8s-operator/issues)

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Share your thoughts on this charm with the community on discourse.

[Join the discussion](https://discourse.charmhub.io/)

Sometimes applications are instrumented with more metrics than we want to afford, from a resources perspective. In such cases we can choose to selectively drop some metrics before they are ingested.

## [Discover high-cardinality metrics](https://charmhub.io/grafana-agent-k8s/docs/drop-metrics#p-31495-discover-high-cardinality-metrics)

Prometheus’s `/tsdb-status` endpoint is quite handy for discovering high cardinality metrics you may want to drop prior to ingestion.

In this guide, we will show how to drop all the `go_gc_*` metrics. To check how many `go_gc_*` metrics you currently have, run the following query:

```
count by (__name__) ({__name__=~"go_gc_.+"})
```

## [Means for dropping metrics](https://charmhub.io/grafana-agent-k8s/docs/drop-metrics#p-31495-means-for-dropping-metrics)

Metrics can be dropped by using the `drop` action in several different places:

* Under [`<scrape_config>`](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#scrape_config) section ([`<metric_relabel_configs>`](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#metric_relabel_configs) subsection). For example: all the self-monitoring scrape jobs that e.g. COS Lite has in place.
* Under [`<remote_write>`](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#remote_write) section (`<write_relabel_configs>` subsection). For example: prometheus can be told to drop metrics before pushing them to another prometheus over remote-write API. This use case is not addressed in this guide.

## [Drop metrics via metric name in scrape config](https://charmhub.io/grafana-agent-k8s/docs/drop-metrics#p-31495-drop-metrics-via-metric-name-in-scrape-config)

Charms that integrate with prometheus or grafana agent, provide a “scrape config” to `MetricsEndpointProvider` (imported from [`charms.prometheus_k8s.v0.prometheus_scrape`](https://charmhub.io/prometheus-k8s/libraries/prometheus_scrape)).

Let’s take for example the alertmanager self-metrics that prometheus scrapes. If we do not want prometheus or grafana agent to ingest any `go_gc_*` metrics from alertmanager, then we need to adjust the scrape job specified in the alertmanager charm:

```
diff --git a/src/charm.py b/src/charm.py
index fa3678c..f0e943b 100755
--- a/src/charm.py
+++ b/src/charm.py
@@ -250,6 +250,13 @@ class AlertmanagerCharm(CharmBase):
             "scheme": metrics_endpoint.scheme,
             "metrics_path": metrics_path,
             "static_configs": [{"targets": [target]}],
+            "metric_relabel_configs": [
+                {
+                    "source_labels": ["__name__"],
+                    "regex": "go_gc_.+",
+                    "action": "drop",
+                }
+            ]
         }

         return [config]
```

## [Drop metrics via the scrape-config charm](https://charmhub.io/grafana-agent-k8s/docs/drop-metrics#p-31495-drop-metrics-via-the-scrape-config-charm)

In a typical scrape-config deployment such as:

```
graph LR
some-external-target --- scrape-target --- scrape-config --- prometheus
```

We can specify the `drop` action via a config option for the scrape-config charm:

```
$ juju config sc metric_relabel_configs="$(cat <<EOF
- source_labels: ["__name__"]
  regex: "go_gc_.+"
  action: "drop"
EOF
)"
```

## [References](https://charmhub.io/grafana-agent-k8s/docs/drop-metrics#p-31495-references)

* Official docs: [`<relabel_config>`](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#relabel_config)
* [Dropping metrics at scrape time with Prometheus](https://www.robustperception.io/dropping-metrics-at-scrape-time-with-prometheus/) (robustperception, 2015)
* [How relabeling in Prometheus works](https://grafana.com/blog/2022/03/21/how-relabeling-in-prometheus-works/) ([grafana.com](http://grafana.com), 2022)
* [How to drop and delete metrics in Prometheus](https://tanmay-bhat.github.io/posts/how-to-drop-and-delete-metrics-in-prometheus/) (gh:tanmay-bhat, 2022)
* Playgrounds:
  + <https://demo.promlens.com/>
  + <https://relabeler.promlabs.com/>

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