testcontainers/testcontainers-java · critical · InvalidConfigurationException

containers are currently not supported

Error message

%s containers are currently not supported

What it means

After picking a Docker strategy, Testcontainers pings the daemon and inspects its OS type. If the daemon reports an osType other than 'linux' (typically 'windows'), tryOutStrategy throws InvalidConfigurationException because Testcontainers only supports Linux containers. The thrown message is the OS type plus 'containers are currently not supported'.

Solutions

  1. Switch Docker Desktop back to Linux containers (system tray icon or `& 'C:\Program Files\Docker\Docker\DockerCli.exe' -SwitchLinuxEngine`)
  2. Point DOCKER_HOST at a Linux-capable daemon (remote Linux host, WSL2 backend)
  3. Verify with `docker info --format '{{.OSType}}'` that the daemon reports linux before running tests
Defensive patterns

Strategy: validation

Validate before calling

// Refuse to run against non-Linux daemons before starting containers
String osType = java.util.Optional.ofNullable(
        new com.github.dockerjava.core.DefaultDockerClientConfig.Builder().build()
            ).orElse(null) != null ? null : null;
Process p = new ProcessBuilder("docker", "info", "--format", "{{.OSType}}").start();
String out = new String(p.getInputStream().readAllBytes()).trim();
if (!"linux".equals(out)) {
    throw new IllegalStateException(out + " containers are not supported; switch Docker to Linux engine");
}

Try / catch

try {
    container.start();
} catch (InvalidConfigurationException e) {
    if (e.getMessage().endsWith("containers are currently not supported")) {
        // switch the daemon to Linux containers and rerun
    }
    throw e;
}

Prevention

When it happens

Trigger: Running tests against a Docker daemon configured for Windows containers (Docker Desktop 'Switch to Windows containers'), so strategy.getInfo().getOsType() returns "windows" and the check `!osType.equals("linux")` fails.

Common situations: Docker Desktop on Windows left in Windows-container mode; CI agents with Windows-container daemons; a daemon reporting a blank/odd osType falls through with only a warning instead.

Understand the failure class

Background: "unsupported platform" / "not supported on this platform" errors: what they mean and how to fix them — this error's family across 47 libraries.

Related errors

AI-assisted analysis of testcontainers/testcontainers-java@8e549514e3 (2026-09-12). Data as JSON: /api/errors/8607275c572a14c2. Report an issue: GitHub.

Appendix: source

Thrown at core/src/main/java/org/testcontainers/dockerclient/DockerClientProviderStrategy.java:303

                log.debug("strategy {} did not pass the test", strategy.getClass().getSimpleName());
                return false;
            }

            strategy.info = strategy.getDockerClient().infoCmd().exec();
            log.info("Found Docker environment with {}", strategy.getDescription());
            log.debug(
                "Transport type: '{}', Docker host: '{}'",
                TestcontainersConfiguration.getInstance().getTransportType(),
                strategy.getTransportConfig().getDockerHost()
            );

            log.debug("Checking Docker OS type for {}", strategy.getDescription());
            String osType = strategy.getInfo().getOsType();
            if (StringUtils.isBlank(osType)) {
                log.warn("Could not determine Docker OS type");
            } else if (!osType.equals("linux")) {
                log.warn("{} is currently not supported", osType);
                throw new InvalidConfigurationException(osType + " containers are currently not supported");
            }

            if (strategy.isPersistable()) {
                TestcontainersConfiguration
                    .getInstance()
                    .updateUserConfig("docker.client.strategy", strategy.getClass().getName());
            }

            return true;
        } catch (Exception | ExceptionInInitializerError | NoClassDefFoundError e) {
            @Nullable
            String throwableMessage = e.getMessage();
            @SuppressWarnings("ThrowableResultOfMethodCallIgnored")
            Throwable rootCause = Throwables.getRootCause(e);
            @Nullable
            String rootCauseMessage = rootCause.getMessage();

            String failureDescription;

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