Chapter 13: Monitoring Basics
13.12 Troubleshooting table
By Ravindra Bagale · Last updated:
| Symptom |
Likely cause |
What to try |
| Prometheus target DOWN |
Exporter down / wrong port / firewall |
curl metrics URL locally; check process |
| Grafana empty panels |
Wrong data source URL or PromQL |
Test query in Prometheus UI first |
| Alert never fires |
Wrong mount label / threshold / for too long |
Validate query returns > threshold now |
| Alert never clears |
File still filling disk / wrong cleanup path |
df -h; remove fill file |
| High cardinailty confusion |
Too many label combinations |
Start with few panels; learn labels slowly |