Introduction

Filebeat not reading logs when input path or registry file issue. This guide provides step-by-step diagnosis and resolution.

Symptoms

Typical error output:

bash
Error: Monitoring operation failed
Check monitoring agent logs
Verify datasource connectivity and configuration

Common Causes

  1. 1.Monitoring agent or server not running
  2. 2.Datasource or target unreachable or authentication issue
  3. 3.Storage capacity exhausted or retention expired
  4. 4.Alert or notification configuration incorrect

Step-by-Step Fix

Step 1: Check Current State

bash
# Check monitoring agent status
systemctl status prometheus grafana-server
# View agent logs
journalctl -u prometheus -n 50
# Check connectivity
curl -v http://prometheus:9090/-/healthy

Step 2: Identify Root Cause

bash
# Check agent configuration
cat /etc/prometheus/prometheus.yml
# Verify targets
curl http://localhost:9090/api/v1/targets
# Check disk space
df -h /var/lib/prometheus

Step 3: Apply Primary Fix

```bash # Primary fix: Check and restart agents # Verify Prometheus status systemctl status prometheus

# Restart monitoring stack systemctl restart prometheus grafana-server alertmanager

# Check disk space df -h /var/lib/prometheus ```

Step 4: Apply Alternative Fix

bash
# Alternative: Check configuration
# Verify scrape targets
curl http://localhost:9090/api/v1/targets
# Check datasource
grafana-cli admin data-migration test
# View error logs
grep -i error /var/log/prometheus/*.log

Step 5: Verify the Fix

bash
curl http://localhost:9090/-/healthy
# Should return "Prometheus is Healthy"
curl http://localhost:3000/api/health
# Grafana should return "ok"

Common Pitfalls

  • Not monitoring the monitoring stack itself
  • Setting retention too short for historical analysis
  • Not testing alert rules before deployment
  • Ignoring disk space warnings for timeseries data

Best Practices

  • Monitor monitoring infrastructure health
  • Set up backup monitoring systems
  • Test all alerts and notifications regularly
  • Keep retention policies aligned with disk capacity
  • Prometheus Scrape Failed
  • Grafana Dashboard Error
  • Alert Not Firing
  • Notification Failed