Custom configuration

You can override some default properties if your environment requires that.

Configuration file location

The configuration will be loaded from multiple locations. Properties are considered in the following order:

  1. in user's home folder. Example locations:
    Linux: /home/myuser/
    Windows: C:/Users/myuser/
    macOS: /Users/myuser/
  2. on classpath

Disabling the startup checks

checks.disable = [true|false]

Before running any containers Testcontainers will perform a set of startup checks to ensure that your environment is configured correctly. Usually they look like this:

        ℹ︎ Checking the system...
        ✔ Docker version should be at least 1.6.0
        ✔ Docker environment should have more than 2GB free disk space
        ✔ File should be mountable
        ✔ A port exposed by a docker container should be accessible
It takes a couple of seconds, but if you want to speed up your tests, you can disable the checks once you have everything configured. Add checks.disable=true to your $HOME/ to completely disable them.

Customizing images

Testcontainers uses public Docker images to perform different actions like startup checks, VNC recording and others. Some companies disallow the usage of Docker Hub, but you can override *.image properties with your own images from your private registry to workaround that.

tinyimage.container.image = alpine:3.5
Used by Testcontainers' core

vncrecorder.container.image = testcontainersofficial/vnc-recorder:1.1.0
Used by VNC recorder in Testcontainers' Seleniun integration

ambassador.container.image = richnorth/ambassador:latest
compose.container.image = docker/compose:1.8.0
Used by Docker Compose integration

kafka.container.image = confluentinc/cp-kafka
Used by KafkaContainer

localstack.container.image = localstack/localstack
Used by LocalStack

Another possibility is to set up a registry mirror in your environment so that all images are pulled from there and not directly from Docker Hub. For more information, see the official Docker documentation about "Registry as a pull through cache".


Registry mirror currently only works for Docker images with image name that has no registry specified (for example, for Docker image mariadb:10.3.6, it works, for Docker image, not).

Customizing Ryuk resource reaper

ryuk.container.image = testcontainersofficial/ryuk:0.3.0 The resource reaper is responsible for container removal and automatic cleanup of dead containers at JVM shutdown

ryuk.container.privileged = false In some environments ryuk must be started in privileged mode to work properly (--privileged flag)

Disabling Ryuk

Ryuk must be started as a privileged container.
If your environment already implements automatic cleanup of containers after the execution, but does not allow starting privileged containers, you can turn off the Ryuk container by setting TESTCONTAINERS_RYUK_DISABLED environment variable to true.


Note that Testcontainers will continue doing the cleanup at JVM's shutdown, unless you kill -9 your JVM process.

Customizing image pull behaviour

pull.pause.timeout = 30 By default Testcontainers will abort the pull of an image if the pull appears stalled (no data transferred) for longer than this duration (in seconds).

Customizing Docker host detection

Testcontainers will attempt to detect the Docker environment and configure everything.

However, sometimes a customization is required. For that, you can provide the following environment variables:

DOCKER_HOST = unix:///var/run/docker.sock
See Docker environment variables

Path to Docker's socket. Used by Ryuk, Docker Compose, and a few other containers that need to perform Docker actions.
Example: /var/run/docker-alt.sock

Docker's host on which ports are exposed.
Example: docker.svc.local