Testcontainers container failed to start

May 15, 2026 · View on GitHub

Playbook ID: testcontainer-startup Category: test Severity: medium Tags: testcontainers, docker, test, integration, container

What this failure means

A test using Testcontainers could not start the required Docker container. This usually means Docker is unavailable on the CI runner, or the runner cannot access the Docker socket.

Common log signals

Could not find a valid Docker environment
DockerClientProviderStrategy
org.testcontainers
container failed to start
Mapped port can only be obtained after the container is started
testcontainers
ProviderError
Ryuk started

Diagnosis

A test using Testcontainers could not start the required Docker container. This usually means Docker is unavailable on the CI runner, or the runner cannot access the Docker socket.

Fix steps

  1. In GitHub Actions, ensure the runner actually has Docker available or add the appropriate Docker service.
  2. In GitLab CI, add docker:dind and configure DOCKER_HOST if the test environment expects it.
  3. If the job runs in a container, confirm /var/run/docker.sock is mounted or the remote Docker endpoint is reachable.
  4. Use TESTCONTAINERS_HOST_OVERRIDE when Docker runs remotely.
  5. Pre-pull large images in CI to avoid cold-start timeouts.

Validation

  • docker info succeeds in the same environment that runs the tests.
  • Re-run the failing test command and confirm the container starts successfully.

Likely files to inspect

  • src/test/
  • docker-compose.yml
  • .github/workflows/*.yml
  • .gitlab-ci.yml

Run Faultline

faultline analyze build.log
faultline explain testcontainer-startup
faultline workflow build.log --json --mode agent

Search phrases this page answers

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  • Mapped port can only be obtained after the container is started
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Generated from playbooks/bundled/log/test/testcontainer-startup.yaml. Do not edit directly — run make docs-generate.