Kubernetes pod stuck in CrashLoopBackOff after scaling beyond 20 replicas

Classic connection pool exhaustion disguised as OOM. Each pod is likely opening its own connection pool to PostgreSQL. At 20 replicas x default pool size of 10, that's 200 connections against PostgreSQL's default max_connections of 100. The pods aren't actually out of memory - they're hanging on connection acquisition, the health check fails, and Kubernetes OOMKills the stalled process. Solution: put PgBouncer in front of PostgreSQL in transaction mode, and reduce per-pod pool size to 3-5.