ceph/src/seastar/doc/prometheus.md

   1 # The Prometheus Protocol
   2
   3 Seastar supports the Prometheus protocol for metrics reporting.
   4 Supported exposition formats are the 0.0.4 text and protocol buffer formats.
   5
   6 More on the formats can be found at the [Prometheus documentations](https://prometheus.io/docs/instrumenting/exposition_formats/)
   7
   8 By default, Seastar would listen on port `9180` and the `localhost`.
   9
  10 See the Seastar configuration documentation on how to change the default configuration.
  11
  12 Seastar would reply based on the content type header, so pointing your browser to:
  13 `http://localhost:9180/metrics/` will return a text representation of the metrics with their documentation.
  14
  15 ## Querying sub set of the metrics
  16 Seastar supports specifying querying a specific metric or a metrics group that share the same prefix.
  17
  18 This is support by both protocols versions.
  19
  20 For example to get all the http metrics in a text format, point your browser to:
  21 `http://localhost:9180/metrics?name=http*` note the asterisk symbol following the http. The Seastar Prometheus API only supports prefix matching.
  22
  23 To query for only the http requests served metric, point your browser to `http://localhost:9180/metrics?name=httpd_requests_served`
  24
  25 ### Configuring the Prometheus server for picking specific metrics
  26 The [Prometheus configuration](https://prometheus.io/docs/prometheus/1.8/configuration/configuration/) describes the general Prometheus configuration.
  27
  28 To specify a specific metric or metrics add a `metrics_path` to the scrap config in the prometheue.yml file
  29
  30 For example, the following scrap config, will query for all the http metrics:
  31
  32 ```
  33   scrape_configs:
  34     - job_name: http
  35       honor_labels: true
  36       metrics_path: /metrics
  37       params:
  38         name: 'http*'
  39 ```
  40