EC
Exit Code 137
DockerERRORCommonRuntimeHIGH confidence

Container killed by OOM killer (SIGKILL)

What this means

Exit code 137 is not a direct application error, but rather a signal from the host's kernel that the process was forcefully terminated. It is calculated as 128 + 9 (SIGKILL). In the context of Docker, this almost always means the container exceeded its memory limit and was killed by the OOM (Out Of Memory) killer.

Why it happens
  1. 1Container memory limit ('--memory') is set too low for the application.
  2. 2The application inside the container has a memory leak.
  3. 3The host machine is out of memory, forcing the kernel to reclaim memory by killing processes.
  4. 4A batch job or data processing task unexpectedly requires a large amount of memory.
How to reproduce

Running a Java application with a small heap size inside a container with a tight memory limit, causing the JVM to request more memory than is available.

trigger — this will error
trigger — this will error
# Run a container with a low memory limit
docker run --memory=128m -d my-java-app
# The application inside attempts to use more than 128MB of RAM
# Check the exit code after it stops
docker wait my-java-app-container-name

expected output

137

Fix 1

Increase Container Memory

WHEN The application's memory requirements are known and have grown.

Increase Container Memory
# Increase memory limit to a more reasonable value
docker run --memory=512m my-java-app

Why this works

Provides more RAM to the container, preventing the OOM killer from being triggered for normal workload.

Fix 2

Inspect Container for OOMKilled State

WHEN You suspect an OOM event but need confirmation.

Inspect Container for OOMKilled State
docker inspect <container_id> --format '{{.State.OOMKilled}}'

Why this works

The Docker daemon records if a container was terminated by the OOM killer. This command confirms the root cause of the Exit 137.

What not to do

✕ Assume Exit 137 is always a memory leak.

While a leak is a common cause, it can also be triggered by legitimate, high-memory workloads or misconfigured limits. Always investigate before assuming.

✕ Disable the OOM killer on the host.

This is extremely dangerous. If the system runs out of memory and cannot kill any process, it will likely lead to a kernel panic and a full system crash.

Sources
Official documentation ↗

Stack Overflow: What does exit code 137 mean for a Docker container?

Understanding and Troubleshooting Exit Code 137 ↗

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