Postmortem

A sudden production incident took down the user authentication system: gateways threw 502 Bad Gateway, while the auth service (Casdoor) returned persistent 503 Service Unavailable. Checking the root partition with df -h showed only 40% disk utilization, with 55GB of free space remaining. Yet system calls across the host crashed with no space left on device (ENOSPC). The culprit was a 6-month-old legacy PHP container. Bypassing broken garbage collection and battered by anonymous crawlers, it quietly generated 5.71 million zero-byte session files in a single flat directory, devouring all 6.35 million inodes available on the host filesystem.