Prometheus, Grafana, and Alertmanager

Prometheus, Grafana, and Alertmanager: An Integrated Monitoring and Alerting System

Comprehensive Monitoring, Visualization, and Alerting
John Korio | 4th October 2024

What is Prometheus?

Prometheus is an open-source monitoring and alerting toolkit designed for reliability and scalability.

Main Features: Pull-based model: Prometheus scrapes metrics from configured targets. Time-series database: Metrics are stored as time-stamped data. PromQL: A powerful query language for aggregating and filtering metrics. Service Discovery: Automatically discovers targets from cloud environments or custom configurations.

Common Use Cases: Monitoring server performance (CPU, memory, disk usage), Application-level metrics (HTTP requests, error rates), Infrastructure monitoring (databases, containers)

How Prometheus Works

Architecture: Prometheus scrapes metrics from configured targets at set intervals. Metrics are stored in a time-series database. Prometheus server: Central component responsible for scraping and storing metrics. Targets: Applications, databases, and systems exposing metrics.

Data Collection Process: Metrics are scraped via HTTP. Each target must expose a /metrics endpoint (e.g., Node Exporter).

PromQL Example: rate(http_requests_total[5m]): Finds the rate of HTTP requests over the past 5 minutes.

What is Grafana?

Grafana is a data visualization platform that provides powerful dashboards and visual representations of real-time metrics.

Key Features: Customizable Dashboards, Multi-source Support (Prometheus, Elasticsearch, etc.), Annotations (mark events on dashboards), Grafana Alerts (set up alerts directly from dashboards).

Use Cases: Real-time infrastructure monitoring, tracking application performance, centralized monitoring for multiple systems and environments.

What is Alertmanager?

Alertmanager is a component in Prometheus that handles alerts generated based on defined rules.

Key Features: Alert Routing (to different receivers like email, Slack), Alert Grouping (reduce noise), Silencing (mute alerts temporarily), Inhibition (prevent cascading alerts).

Use Cases: Notify DevOps teams when infrastructure or services go down, configure alerts for metric thresholds (e.g., CPU > 80%).

Alertmanager Architecture

Alert Flow: Prometheus evaluates alert rules. Alerts are sent to Alertmanager, which routes them to the appropriate channel (email, Slack, etc.).

Example: A high CPU alert triggers in Prometheus. Alertmanager routes it to Slack based on the configuration. The alert is grouped and notified to the appropriate team.

Prometheus + Grafana + Alertmanager Integration

Monitoring Workflow: Prometheus scrapes and stores metrics, Grafana visualizes metrics via custom dashboards, and Alertmanager handles alert notifications.

Example: Prometheus scrapes HTTP requests metrics. Grafana visualizes requests and displays alert thresholds. Alertmanager triggers an alert when thresholds are exceeded.

Windows Exporter for Monitoring Windows Servers

What is Windows Exporter: An open-source exporter for Prometheus that collects hardware and OS metrics from Windows systems.

Metrics Monitored: CPU usage, Memory utilization, Disk I/O and free space, Network traffic, Windows services, and processes.

Node Exporter for Monitoring Linux Servers

What is Node Exporter: An open-source exporter that exposes hardware and OS metrics from Linux servers, commonly used for collecting Linux server metrics in Prometheus.

Metrics Monitored: CPU usage, Memory utilization, Disk I/O, Network bandwidth and errors, File system statistics.

Best Practices

Prometheus: Use service discovery for dynamic environments, keep data retention periods manageable, optimize scrape intervals for resource efficiency.

Grafana: Organize dashboards by team or service, use variables to create dynamic and reusable dashboards.

Alertmanager: Group and deduplicate alerts to avoid alert fatigue. Set up inhibition rules to avoid redundant alerts. Test alert configurations regularly.

Resources and References

Prometheus Security: A Guide to TLS and Basic Authentication… | by Abdullah Eid | Medium
AlertManager and Prometheus Complete Setup on Linux – devconnected
Install Grafana on Debian or Ubuntu | Grafana documentation
Configure security | Grafana documentation
Set up Grafana HTTPS for secure web traffic | Grafana documentation
Installation | Prometheus
YouTube Tutorial