# Scrape selective metrics in Prometheus

> Recipe to only scrape selective metrics in Prometheus to reduce cardinality

Source: https://last9.io/docs/how-to-scrape-only-selective-metrics-in-prometheus/

Prometheus provides the ability to filter specific metrics post-scraping, via
the `metrics_relabel_config` stanza.

:::tip
This is useful in reducing the number of metrics before they are consumed and sent to a remote write long term storage.
:::

We will use the `node_exporter` Prometheus exporter as an example, and send only
metrics matching the regex `node_cpu.*`.

## Prometheus scrape config without filtering

```shell
global:
  scrape_interval: 1m

scrape_configs:
  - job_name: 'node-exporter-01'
    static_configs:
      - targets: [ 'localhost:9100' ]
```

This scrapes and stores all node exporter metrics.

## Prometheus scrape config with filtering

```bash
global:
  scrape_interval: 1m

scrape_configs:
  - job_name: 'node-exporter-01'
    static_configs:
      - targets: [ 'localhost:9100' ]
    metric_relabel_configs:
    - source_labels: [__name__]
      action: keep
      regex: '(node_cpu)'
```

This will scrape all metrics, but drop anything that does not match the entries
in the `regex` section.