Running testcontainers-java inside a distrobox

[rombert]

Hi,

My current host is Ubuntu Linux 24.04 and I am using distrobox to set up a Docker container for development. That container is based on openSUSE Tumbleweed, but that is less important.

Inside my dev docker container, I want to run testcontainers-java based tests. When I run the test using Maven, I get the following

[INFO] -------------------------------------------------------
[INFO]  T E S T S
[INFO] -------------------------------------------------------
[INFO] Running org.apache.sling.servlets.oidc_rp.AuthorizationCodeFlowIT
[main] WARN org.testcontainers.utility.TestcontainersConfiguration - Attempted to read Testcontainers configuration file at file:/home/robert/.testcontainers.properties but the file was not found. Exception message: FileNotFoundException: /home/robert/.testcontainers.properties (No such file or directory)
[main] INFO org.testcontainers.utility.ImageNameSubstitutor - Image name substitution will be performed by: DefaultImageNameSubstitutor (composite of 'ConfigurationFileImageNameSubstitutor' and 'PrefixingImageNameSubstitutor')
[main] WARN org.testcontainers.dockerclient.DockerClientProviderStrategy - DOCKER_HOST unix:///var/run/docker.sock is not listening
[main] INFO org.testcontainers.dockerclient.DockerMachineClientProviderStrategy - docker-machine executable was not found on PATH ([/usr/local/sbin, /usr/local/bin, /usr/sbin, /usr/bin, /sbin, /bin, /usr/games, /usr/local/games, /snap/bin, /snap/bin, /usr/local/sbin, /usr/local/bin, /usr/sbin, /usr/bin, /sbin, /bin])
[main] ERROR org.testcontainers.dockerclient.DockerClientProviderStrategy - Could not find a valid Docker environment. Please check configuration. Attempted configurations were:
As no valid configuration was found, execution cannot continue.
See https://www.testcontainers.org/on_failure.html for more details.
[ERROR] Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.147 s <<< FAILURE! - in org.apache.sling.servlets.oidc_rp.AuthorizationCodeFlowIT
[ERROR] org.apache.sling.servlets.oidc_rp.AuthorizationCodeFlowIT.accessTokenIsPresentOnSuccessfulLogin  Time elapsed: 0.133 s  <<< ERROR!
org.testcontainers.containers.ContainerFetchException: Can't get Docker image: RemoteDockerImage(imageName=quay.io/keycloak/keycloak:20.0.3, imagePullPolicy=DefaultPullPolicy(), imageNameSubstitutor=org.testcontainers.utility.ImageNameSubstitutor$LogWrappedImageNameSubstitutor@7749bf93)

I have the docker socket mounted in the dev container

$ ll /var/run/docker.sock
lrwxrwxrwx 1 root root 25 Aug 15 16:12 /var/run/docker.sock -> /run/host/run/docker.sock=
$ ll /run/host/run/docker.sock 
srw-rw---- 1 root 125 0 Aug 21 11:27 /run/host/run/docker.sock=

Additionally (and maybe confusingly), the docker command in my dev container delegates to the host docker command. But, as far as I understand, that should not matter to testcontainers-java.

$ docker context ls
NAME        DESCRIPTION                               DOCKER ENDPOINT               ERROR
default *   Current DOCKER_HOST based configuration   unix:///var/run/docker.sock

How can I fix this or debug this further?

[rombert]

I did the following changes to fix the setup:

• identified the docker group id on the host ( stat /var/run/docker.sock )
• created a group with the matching id in the distrobox container ( sudo groupadd -g 125 hostdocker )
• added my own user to that group in the container ( sudo usermod -aG 125 $USER)

After existing and re-entering the container I could run the tests as expected.