* Removing some labels from metrics matching some [series selector](https://prometheus.io/docs/prometheus/latest/querying/basics/#time-series-selectors).
See [how to remove labels from metrics subset](#how-to-remove-labels-from-metrics-subset).
- [how to remove labels from scraped metrics](#how-to-remove-labels-from-scraped-metrics)
- [useful tips for metric relabeling](#useful-tips-for-metric-relabeling)
## How to rename scraped metrics
Metric name is a regular label with special name - `__name__` (see [these docs](https://docs.victoriametrics.com/keyconcepts/#labels)).
So renaming of metric name is performed in the same way as changing label value.
Let's look at a few examples.
The following config renames `foo` metric to `bar` across all the scraped metrics, while leaving other metric names as is:
```yaml
scrape_configs:
- job_name: test
static_configs:
- targets: [host123]
metric_relabel_configs:
- if: 'foo'
replacement: bar
target_label: __name__
```
The following config renames metrics starting from `foo_` to metrics starting from `bar_` across all the scraped metrics. For example, `foo_count` is renamed to `bar_count`:
```yaml
scrape_configs:
- job_name: test
static_configs:
- targets: [host123]
metric_relabel_configs:
- source_labels: [__name__]
regex: 'foo_(.*)'
replacement: bar_$1
target_label: __name__
```
The following config replaces all the `-` chars in metric names with `_` chars across all the scraped metrics. For example, `foo-bar-baz` is renamed to `foo_bar_baz`:
```yaml
scrape_configs:
- job_name: test
static_configs:
- targets: [host123]
metric_relabel_configs:
- source_labels: [__name__]
action: replace_all
regex: '-'
replacement: '_'
target_label: __name__
```
See also [useful tips for metric relabeling](#useful-tips-for-metric-relabeling).
## How to add labels to scraped metrics
The following config sets `foo="bar"` [label](https://docs.victoriametrics.com/keyconcepts/#labels) across all the scraped metrics:
```yaml
scrape_configs:
- job_name: test
static_configs:
- targets: [host123]
metric_relabel_configs:
- target_label: foo
replacement: bar
```
The following config sets `foo="bar"` label only for metrics matching `{job=~"my-app-.*",env!="dev"}` [series selector](https://docs.victoriametrics.com/keyconcepts/#filtering):
```yaml
scrape_configs:
- job_name: test
static_configs:
- targets: [host123]
metric_relabel_configs:
- if: '{job=~"my-app-.*",env!="dev"}'
target_label: foo
replacement: bar
```
See also [useful tips for metric relabeling](#useful-tips-for-metric-relabeling).
## How to change label values in scraped metrics
The following config adds `foo_` prefix to all the values of `job` label across all the scraped metrics:
```yaml
scrape_configs:
- job_name: test
static_configs:
- targets: [host123]
metric_relabel_configs:
- source_labels: [job]
target_label: job
replacement: foo_$1
```
The following config adds `foo_` prefix to `job` label values only for metrics
and different values will be pushed to the storage. This is an undesired issue in most cases.
See also [useful tips for metric relabeling](#useful-tips-for-metric-relabeling).
## How to drop metrics during scrape
Sometimes it is needed to drop some metrics during scrapes. For example, if some metrics result
in [high cardinality](https://docs.victoriametrics.com/FAQ.html#what-is-high-cardinality)
or [high churn rate](https://docs.victoriametrics.com/FAQ.html#what-is-high-churn-rate) issues,
then it may be a good idea to drop these metrics during scrapes. This can be done with the `action: drop` or `action: keep`
relabeling rules at `metric_relabel_configs` section:
*`action: drop` drops all the metrics, which match the `if` [series selector](https://prometheus.io/docs/prometheus/latest/querying/basics/#time-series-selectors)
*`action: keep` drops all the metrics, which don't match the `if` [series selector](https://prometheus.io/docs/prometheus/latest/querying/basics/#time-series-selectors)
Sometimes it is needed to remove `__meta_*` prefixes from meta-labels of the [discovered targets](https://docs.victoriametrics.com/sd_configs/).
For example, [Kubernetes service discovery](https://docs.victoriametrics.com/sd_configs/#kubernetes_sd_configs) adds `__meta_kubernetes_pod_label_<labelname>`
The `regex` option can contain arbitrary regular expression in [RE2 format](https://github.com/google/re2/wiki/Syntax).
The `regex` option is automatically anchored, so it must match the whole value from `source_labels`.
It can contain capture groups such as `(.+)` in the config above. These capture groups can be referenced then inside `replacement` option
with the `$N` syntax, where `N` is the number of the capture group in `regex`. The first capture group has the `$1` reference.
It is possible to construct a label from multiple parts of different labels. In this case just specify the needed source labels inside `source_labels` list.
The values of labels specified in `source_labels` list are joined with `;` separator by default before being matched against the `regex`.
If the `regex` doesn't match the value constructed from `source_labels`, then the relabeling rule is skipped and the remaining relabeling rules are executed.
See also [useful tips for target relabeling](#useful-tips-for-target-relabeling).
Single-node VictoriaMetrics and [vmagent](https://docs.victoriametrics.com/vmagent/) automatically add `instance` and `job` labels per each discovered target:
* The `job` label is set to `job_name` value specified in the corresponding [scrape_config](https://docs.victoriametrics.com/sd_configs/#scrape_configs).
in [Prometheus text exposition format](https://github.com/prometheus/docs/blob/main/content/docs/instrumenting/exposition_formats.md#text-based-format)
at the resulting scrape url.
Given the scrape url construction rules above, the following config discovers pod targets
For example, the following config adds `{foo="bar"}` label to all the discovered pods in [Kubernetes](https://docs.victoriametrics.com/sd_configs/#kubernetes_sd_configs):
The labels, which are added to the target, are automatically added to all the metrics scraped from the target.
For example, if the target exposes the metric `metric{label="value"}`, then the metric is transformed into `metric{label="value",foo="bar"}`
before being sent to the storage.
If the metric exported by the target contains the same label as the target itself, then the `exported_` prefix is added to the exported label name.
For example, if the target exposes the metric `metric{foo="baz"}`, then the metric is transformed into `metric{exported_foo="baz",foo="bar"}`.
This behaviour can be changed by specifying `honor_labels: true` option at the given scrape config. In this case the exported label overrides
the target's label. In this case the `metric{foo="baz"}` stays the same. Example config with `honor_labels: true`:
```yaml
scrape_configs:
- job_name: k8s
kubernetes_sd_configs:
- role: pod
honor_labels: true
relabel_configs:
- target_label: "foo"
replacement: "bar"
```
See also [useful tips for target relabeling](#useful-tips-for-target-relabeling).
## How to drop discovered targets
If a particular discovered target shouldn't be scraped, then `action: keep` or `action: drop` relabeling rules
must be used inside `relabel_configs` section.
The `action: keep` keeps only scrape targets with labels matching the `if` [selector](https://prometheus.io/docs/prometheus/latest/querying/basics/#time-series-selectors),
while dropping the rest of targets. For example, the following config discovers pod targets in [Kubernetes](https://docs.victoriametrics.com/sd_configs/#kubernetes_sd_configs)
and scrapes only pods with names starting with `foo` prefix:
```yaml
scrape_configs:
- job_name: foo_pods
kubernetes_sd_configs:
- role: pod
relabel_configs:
- if: '{__meta_kubernetes_pod_name=~"foo.*"}'
action: keep
```
The `action: drop` drops all the scrape targets with labels matching the `if` [selector](https://prometheus.io/docs/prometheus/latest/querying/basics/#time-series-selectors),
while keeping the rest of targets. For example, the following config discovers pod targets in [Kubernetes](https://docs.victoriametrics.com/sd_configs/#kubernetes_sd_configs)
