> ## Documentation Index
> Fetch the complete documentation index at: https://private-7c7dfe99-fix-nav-issues.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

> Documentation for the Prometheus protocol support in ClickHouse

# Prometheus protocols

<h2 id="expose">
  Exposing metrics
</h2>

<Note>
  If you're using ClickHouse Cloud, you can expose metrics to Prometheus using the [Prometheus Integration](/products/cloud/features/monitoring/prometheus).
</Note>

ClickHouse can expose its own metrics for scraping from Prometheus:

````xml theme={null}
<prometheus>
    <port>9363</port>
    <endpoint>/metrics</endpoint>
    <metrics>true</metrics>
    <asynchronous_metrics>true</asynchronous_metrics>
    <events>true</events>
    <errors>true</errors>
    <histograms>true</histograms>
    <dimensional_metrics>true</dimensional_metrics>
</prometheus>

Section `<prometheus.handlers>` can be used to make more extended handlers.
This section is similar to [<http_handlers>](/concepts/features/interfaces/http) but works for prometheus protocols:

```xml
<prometheus>
    <port>9363</port>
    <handlers>
        <my_rule_1>
            <url>/metrics</url>
            <handler>
                <type>expose_metrics</type>
                <metrics>true</metrics>
                <asynchronous_metrics>true</asynchronous_metrics>
                <events>true</events>
                <errors>true</errors>
                <histograms>true</histograms>
                <dimensional_metrics>true</dimensional_metrics>
            </handler>
        </my_rule_1>
    </handlers>
</prometheus>
````

Settings:

| Name                         | Default    | Description                                                                                                                                                                              |
| ---------------------------- | ---------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `port`                       | none       | Port for serving the exposing metrics protocol.                                                                                                                                          |
| `endpoint`                   | `/metrics` | HTTP endpoint for scraping metrics by prometheus server. Starts with `/`. Should not be used with the `<handlers>` section.                                                              |
| `url` / `headers` / `method` | none       | Filters used to find a matching handler for a request. Similar to the fields with the same names in the [`<http_handlers>`](/concepts/features/interfaces/http) section.                 |
| `metrics`                    | true       | Expose metrics from the [system.metrics](/reference/system-tables/metrics) table.                                                                                                        |
| `asynchronous_metrics`       | true       | Expose current metrics values from the [system.asynchronous\_metrics](/reference/system-tables/asynchronous_metrics) table.                                                              |
| `events`                     | true       | Expose metrics from the [system.events](/reference/system-tables/events) table.                                                                                                          |
| `errors`                     | true       | Expose the number of errors by error codes occurred since the last server restart. This information could be obtained from the [system.errors](/reference/system-tables/errors) as well. |
| `histograms`                 | true       | Expose histogram metrics from [system.histogram\_metrics](/reference/system-tables/histogram_metrics)                                                                                    |
| `dimensional_metrics`        | true       | Expose dimensional metrics from [system.dimensional\_metrics](/reference/system-tables/dimensional_metrics)                                                                              |

Check (replace `127.0.0.1` with the IP addr or hostname of your ClickHouse server):

```bash theme={null}
curl 127.0.0.1:9363/metrics
```

<h2 id="remote-write">
  Remote-write protocol
</h2>

ClickHouse supports the [remote-write](https://prometheus.io/docs/specs/remote_write_spec/) protocol.
Data are received by this protocol and written to a [TimeSeries](/reference/engines/table-engines/integrations/time-series) table
(which should be created beforehand).

```xml theme={null}
<prometheus>
    <port>9363</port>
    <handlers>
        <my_rule_1>
            <url>/write</url>
            <handler>
                <type>remote_write</type>
                <database>db_name</database>
                <table>time_series_table</table>
            </handler>
        </my_rule_1>
    </handlers>
</prometheus>
```

Settings:

| Name                         | Default | Description                                                                                                                                                                                                     |
| ---------------------------- | ------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `port`                       | none    | Port for serving the `remote-write` protocol.                                                                                                                                                                   |
| `url` / `headers` / `method` | none    | Filters used to find a matching handler for a request. Similar to the fields with the same names in the [`<http_handlers>`](/concepts/features/interfaces/http) section.                                        |
| `table`                      | none    | The name of a [TimeSeries](/reference/engines/table-engines/integrations/time-series) table to write data received by the `remote-write` protocol. This name can optionally contain the name of a database too. |
| `database`                   | none    | The name of a database where the table specified in the `table` setting is located if it's not specified in the `table` setting.                                                                                |

<h2 id="remote-read">
  Remote-read protocol
</h2>

ClickHouse supports the [remote-read](https://prometheus.io/docs/prometheus/latest/querying/remote_read_api/) protocol.
Data are read from a [TimeSeries](/reference/engines/table-engines/integrations/time-series) table and sent via this protocol.

```xml theme={null}
<prometheus>
    <port>9363</port>
    <handlers>
        <my_rule_1>
            <url>/read</url>
            <handler>
                <type>remote_read</type>
                <database>db_name</database>
                <table>time_series_table</table>
            </handler>
        </my_rule_1>
    </handlers>
</prometheus>
```

Settings:

| Name                         | Default | Description                                                                                                                                                                                                  |
| ---------------------------- | ------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `port`                       | none    | Port for serving the `remote-read` protocol.                                                                                                                                                                 |
| `url` / `headers` / `method` | none    | Filters used to find a matching handler for a request. Similar to the fields with the same names in the [`<http_handlers>`](/concepts/features/interfaces/http) section.                                     |
| `table`                      | none    | The name of a [TimeSeries](/reference/engines/table-engines/integrations/time-series) table to read data to send by the `remote-read` protocol. This name can optionally contain the name of a database too. |
| `database`                   | none    | The name of a database where the table specified in the `table` setting is located if it's not specified in the `table` setting.                                                                             |

<h2 id="multiple-protocols">
  Configuration for multiple protocols
</h2>

Multiple protocols can be specified together in one place:

```xml theme={null}
<prometheus>
    <port>9363</port>
    <handlers>
        <my_rule_1>
            <url>/metrics</url>
            <handler>
                <type>expose_metrics</type>
                <metrics>true</metrics>
                <asynchronous_metrics>true</asynchronous_metrics>
                <events>true</events>
                <errors>true</errors>
                <histograms>true</histograms>
                <dimensional_metrics>true</dimensional_metrics>
            </handler>
        </my_rule_1>
        <my_rule_2>
            <url>/write</url>
            <handler>
                <type>remote_write</type>
                <table>db_name.time_series_table</table>
            </handler>
        </my_rule_2>
        <my_rule_3>
            <url>/read</url>
            <handler>
                <type>remote_read</type>
                <table>db_name.time_series_table</table>
            </handler>
        </my_rule_3>
    </handlers>
</prometheus>
```