# Testcontainers "Container startup failed" in CI - Fix Container Boot

> Fix Testcontainers "Container startup failed" in CI - a container did not become ready (wait strategy, image pull, port, or resources). Latchkey runners auto-retry transient blips.

Source: https://latchkey.dev/learn/java-jvm/testcontainers-container-startup-failed-ci  
Updated: 2026-06-26

Testcontainers starts a container and waits until it is "ready" per a wait strategy. "Container startup failed" means readiness was never reached in time - a slow/failed image pull, a wrong wait condition, an exhausted port, or the container crashing on boot.

## Diagnose it: JDK version and heap

```Terminal
java -version 2>&1
echo "JAVA_HOME=$JAVA_HOME"
free -h

# class file 65 = Java 21, 61 = Java 17, 55 = Java 11
javap -verbose <SomeClass>.class | grep "major version"
```

> An unsupported class file version is a JDK mismatch, not a code error. Exit 137 during a build is the out-of-memory killer, which no JVM flag in the build file will explain.

## FAQ

### What causes Testcontainers "Container startup failed" in CI?

There are 2 common causes: wait strategy or readiness timeout and image pull or container crash on boot. The default/declared wait strategy did not match how the container signals readiness, or the container was slow to start within the timeout (sometimes transient under load).

### How do I fix Testcontainers "Container startup failed" in CI?

There are 2 fixes depending on which cause you have: use an accurate wait strategy with headroom and diagnose the boot failure. Work through them in order, since the first is the most common.

### What does Testcontainers "Container startup failed" in CI actually mean?

A @Testcontainers test fails with ContainerLaunchException: Container startup failed or Timed out waiting for container port to open / Wait strategy failed.

### How do I stop Testcontainers "Container startup failed" in CI happening again?

Pin and pre-pull images, set readiness-accurate wait strategies with adequate timeouts, and validate container config so startup is reliable.

### Can Latchkey fix this automatically?

Yes. Latchkey runs your GitHub Actions on managed runners that detect this failure, apply the fix, and retry the job automatically - self-healing is on by default.

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Latchkey runs CI/CD that repairs its own failures. Agent entry points: https://latchkey.dev/agent.txt, https://latchkey.dev/openapi.json, https://latchkey.dev/llms.txt