Overview

What is Prometheus?

• Prometheus is an open-source systems monitoring and alerting toolkit
• Prometheus collects and stores its metrics as time series data, i.e. metrics information is stored with the timestamp at which it was recorded, alongside optional key-value pairs called labels.
• time series collection happens via a pull model over HTTP

Components

• the main Prometheus server which scrapes and stores time series data
• client libraries for instrumenting application code
• a push gateway for supporting short-lived jobs

Downloading Prometheus

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tar xvfz prometheus-*.tar.gz
cd prometheus-*
./prometheus --help

Configuring Prometheus

• The Prometheus download comes with a sample configuration in a file called prometheus.yml

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global:
  scrape_interval:     15s
  evaluation_interval: 15s

rule_files:
  # - "first.rules"
  # - "second.rules"

scrape_configs:
  - job_name: prometheus
    static_configs:
      - targets: ['localhost:9090']

• scrape_interval, controls how often Prometheus will scrape targets. You can override this for individual targets.
• The evaluation_interval option controls how often Prometheus will evaluate rules. Prometheus uses rules to create new time series and to generate alerts.
• The rule_files block specifies the location of any rules we want the Prometheus server to load.
• The last block, scrape_configs, controls what resources Prometheus monitors.
• Prometheus expects metrics to be available on targets on a path of /metrics.

Starting Prometheus

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./prometheus --config.file=prometheus.yml