Gather Metrics from Fluent Bit pipeline
Fluent Bit comes with a built-in HTTP Server that can be used to query internal information and monitor metrics of each running plugin.
The monitoring interface can be easily integrated with Prometheus since we support it native format.
To get started, the first step is to enable the HTTP Server from the configuration file:
the above configuration snippet will instruct Fluent Bit to start it HTTP Server on TCP Port 2020 and listening on all network interfaces:
now with a simple curl command is enough to gather some information:
Note that we are sending the curl command output to the jq program which helps to make the JSON data easy to read from the terminal. Fluent Bit don't aim to do JSON pretty-printing.
Fluent Bit aims to expose useful interfaces for monitoring, as of Fluent Bit v0.14 the following end points are available:
Query the service uptime with the following command:
it should print a similar output like this:
Query internal metrics in JSON format with the following command:
it should print a similar output like this:
Query internal metrics in Prometheus Text 0.0.4 format:
this time the same metrics will be in Prometheus format instead of JSON:
By default configured plugins on runtime get an internal name in the format plugin_name.ID. For monitoring purposes this can be confusing if many plugins of the same type were configured. To make a distinction each configured input or output section can get an alias that will be used as the parent name for the metric.
The following example set an alias to the INPUT section which is using the CPU input plugin:
Now when querying the metrics we get the aliases in place instead of the plugin name:
URI
Description
Data Format
/
Fluent Bit build information
JSON
/api/v1/uptime
Get uptime information in seconds and human readable format
JSON
/api/v1/metrics
Internal metrics per loaded plugin
JSON
/api/v1/metrics/prometheus
Internal metrics per loaded plugin ready to be consumed by a Prometheus Server
Prometheus Text 0.0.4