Custom configuration

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

Configuration locations

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

  1. Environment variables
  2. .testcontainers.properties in user's home folder. Example locations:
    Linux: /home/myuser/.testcontainers.properties
    Windows: C:/Users/myuser/.testcontainers.properties
    macOS: /Users/myuser/.testcontainers.properties
  3. testcontainers.properties on the classpath.

Note that when using environment variables, configuration property names should be set in upper case with underscore separators, preceded by TESTCONTAINERS_ - e.g. checks.disable becomes TESTCONTAINERS_CHECKS_DISABLE.

The classpath testcontainers.properties file may exist within the local codebase (e.g. within the src/test/resources directory) or within library dependencies that you may have. Any such configuration files will have their contents merged. If any keys conflict, the value will be taken on the basis of the first value found in:

  • 'local' classpath (i.e. where the URL of the file on the classpath begins with file:), then
  • other classpath locations (i.e. JAR files) - considered in alphabetical order of path to provide deterministic ordering.

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/.testcontainers.properties to completely disable them.

Customizing images

Note

This approach is discouraged and deprecated, but is documented for completeness. Overriding individual image names via configuration may be removed in 2021. See Image Name Substitution for other strategies for substituting image names to pull from other registries.

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.

ryuk.container.image = testcontainers/ryuk:0.3.0 Performs fail-safe cleanup of containers, and always required (unless Ryuk is disabled)

tinyimage.container.image = alpine:3.5
Used to check whether images can be pulled at startup, and always required (unless startup checks are disabled)

sshd.container.image = testcontainers/sshd:1.0.0
Required if exposing host ports to containers

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

socat.container.image = alpine/socat
compose.container.image = docker/compose:1.8.0
Required if using Docker Compose

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

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

pulsar.container.image = apachepulsar/pulsar:2.2.0
Used by Apache Pulsar

Customizing Ryuk resource reaper

ryuk.container.image = testcontainers/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.

Tip

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

TESTCONTAINERS_DOCKER_SOCKET_OVERRIDE
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

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