What Happened

Our production Kubernetes cluster experienced a complete outage when all worker nodes ran out of disk space simultaneously. This was caused by:

1. Unbounded log growth from a misconfigured application
2. No disk space monitoring alerts
3. Default emptyDir volumes filling up node storage

The Impact

• All pods became pending as nodes were marked unschedulable
• 4 hours of downtime during peak traffic
• Data loss for applications using emptyDir storage

Lessons Learned

1. Monitor disk usage: Set up alerts at 70%, 80%, and 90% capacity
2. Log rotation: Configure proper log rotation for all containers
3. Resource limits: Set storage limits on emptyDir volumes
4. Multi-zone deployment: Distribute workloads across availability zones

The Fix

We implemented: