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Monitoring with Prometheus

The Halon MTA can be easily monitored using Prometheus with the help of their Node Exporter.

Exporting the metrics​

Below is an example on how you can use the halonctl process-stats command to export the values in their text-based format.

halonctl process-stats --openmetrics > /halon-stats/process-stats.prom.$$
mv /halon-stats/process-stats.prom.$$ /halon-stats/process-stats.prom

This command can then easily be ran in a cronjob and then you can have the output be parsed by Node Exporter like this:

node_exporter --collector.disable-defaults \
              --collector.textfile \
              --collector.textfile.directory=/halon-stats
tip

You can use http://localhost:9100/metrics to verify that the metrics are populated correctly.

Fetching the metrics​

Finally you can configure Prometheus to fetch the data from Node Exporter like this:

/etc/prometheus/prometheus.yml
global:
  scrape_interval: 1m
scrape_configs:
  - job_name: halon
    static_configs:
      - targets: ["localhost:9100"]
tip

You can use http://localhost:9090/graph to verify that the metrics are populated correctly.