How to use monitor custom application with mflib Prometheus

[Acheme Acheme]

Hello,

My interest is to generate metrics from my python code and use prometheus server installed with mflib to scrape the metrics from the application target.

1. Please can someone show me a quick step to achieve this
2. Or specifically, how do I edit the prometheus config file in the docker container installed on the measurement node with mflib

Thank you very much.

Regards,

Acheme

[Charles Carpenter]

There are a couple of methods to export metrics from your running python code.

For a general overview on writing prometheus exporters see https://prometheus.io/docs/instrumenting/writing_exporters/

Option 1) Create your own exporter in python. This will run a small http server and will allow Prometheus to query your code every x seconds (30 seconds is usually the default). This is best for a consistently running process. Python has a promtheus_client module, pip install prometheus-client that handles most of the work for you. You will need to add a function that will be called whenever a prometheus instance makes the request. See https://prometheus.github.io/client_python/getting-started/three-step-demo/  and  https://pypi.org/project/prometheus-client/  and  https://github.com/prometheus/client_python

You can do a test of the running exporter using curl or wget with the address of the exporter and the path /metrics.

Next configure the prometheus on the meas_node to scrape your newly created exporter. The config file is /opt/fabric_prometheus/prometheus/prometheus_config.yml . ssh to the meas_node and sudo vim /opt/fabric_prometheus/prometheus/prometheus_config.yml Add the new scrape section at the end of the file.

Something like

 

# My Exporter
- job_name: 'my_exporter_name'
  static_configs:
  - targets: ['my-exporter-address:port']

The scrape will default to the /metrics path.

Save the file and

docker restart fabric_prometheus_prometheus

Use the Explore tab in Grafana with the PromQl {job=”my_exporter_name”} to see the metrics.

 

Option 2) Use the node_exporters textfile collector. This is best for sporatic metrics, perhaps a cron job that runs hourly. The collector reads text files found in the /var/lib/node_exporter directory. The files need to be in the format found at https://prometheus.io/docs/instrumenting/exposition_formats/#text-based-format There is a python module for writing out text files See https://prometheus.github.io/client_python/exporting/textfile/ https://github.com/prometheus/node_exporter#textfile-collector

That should get you started. Let me know if you have more questions.
-Charles

 

[Acheme Acheme]

Thank you very much Charles.

Found out the config file path is actually /opt/fabric_prometheus/prometheus/config/prometheus_config.yml

Regards,

Acheme

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