How Docker Broke the Internet for Me

We have seen two major outages in the last weeks caused by AWS and Azure networking issues. Both outages had a significant impact on services running in the cloud and affected a large number of users. The self-hosting people were laughing about it, but some got struck with the recent Docker 29.0.0 release. It simply increased the minimal API version from 1.24 to 1.44.

This change broke Traefik and some tooling, like the testcontainers-java. The maintainers of Traefik already released a fix, and probably created some stress for them. A lot of issues poped up in their GitHub repository, like this one https://github.com/traefik/traefik/pull/12256. I felt sorry for them, many users use their stuff - including me - to drive HTTP/HTTPS traffic to their websites. It was great to see how quickly shared workarounds. The Traefik maintainers were able to provide and ship a fix in a new release very quickly. All you need to do is upgrade to 3.6.1, and you are good to go again.

I ran immediately in a second issue running our container based end-to-end tests with testcontainers-java. Running the test, I was greeted with the following error message:

23:23:25.087 [main] ERROR org.testcontainers.dockerclient.DockerClientProviderStrategy - Could not find a valid Docker environment. Please check configuration. Attempted configurations were:
	UnixSocketClientProviderStrategy: failed with exception BadRequestException (Status 400: {"message":"client version 1.32 is too old. Minimum supported API version is 1.44, please upgrade your client to a newer version"}
)
	DockerDesktopClientProviderStrategy: failed with exception NullPointerException (Cannot invoke "java.nio.file.Path.toString()" because the return value of "org.testcontainers.dockerclient.DockerDesktopClientProviderStrategy.getSocketPath()" is null)As no valid configuration was found, execution cannot continue.

Instead of downgrading Docker, I decided to just force the minimal API version back to 1.24. You can do this by setting the environment variable DOCKER_API_VERSION to 1.24. This way, you can continue using the latest Docker release and avoid downgrading.

I have documented the workaround in the OpenNMS Discourse forum End-to-End and Smoke Test execution with Docker 29.0.0 is failing. The permanent fix will be upgrading our testcontainers-java dependency to at least 2.0.2 that supports the new Docker API version.

What’s dazzling to me is why project maintainers haven’t seen it coming. Docker is a widely used container runtime, and changing the minimal API version is a significant change that can have far-reaching consequences. The question to maintainers would be why that change hasn’t reached maintainers earlier. If you are affected by this issue, I hope this workaround helps you to get back on track quickly.

Happy hacking!