DockerAmazon ECS

Container Memory Hard Limit Terminations

critical
reliabilityUpdated Nov 6, 2025

ECS terminates containers that exceed hard memory limits, causing unexpected task failures. Containers often fail silently without warning when memory allocation is approached.

Sources
AWS ECS metrics | Vector documentationvector.dev
Ecs Fargate Memory And CPU - TechBloatwww.techbloat.com
Catch and remediate ECS issues faster with default monitors and the ECS Explorer | Datadogwww.datadoghq.com
Key Amazon ECS Metrics to Monitor - Site24x7 Learnsite24x7.com
Technologies:
DockerSymptoms of this issue are visible in Docker metrics and logs
Amazon ECSThe root cause of this issue originates in Amazon ECS
How to detect:

Monitor memory_used_bytes approaching memory_limit_bytes. Track memory_major_faults_total and out-of-memory (OOM) events in container logs. Watch for sudden task terminations correlated with memory_utilization_percent exceeding 90%.

Recommended action:

Set soft limits (MemoryReservation) alongside hard limits (MemoryAllocation) to enable graceful degradation. Configure CloudWatch alarms at 80% memory utilization. Adjust task definition memory limits based on observed usage patterns. Implement memory leak detection for long-running containers.