[🐛 Bug]: standalone-docker not compatible with docker v29 (socket)

[richard-kramer-work]

What happened?

Trying to use standalone-docker with docker v29 socket mounted results in this error: Unable to reach the Docker daemon at http://127.0.0.1:2375

Command used to start Selenium Grid with Docker (or Kubernetes)

docker run --rm -v /var/run/docker.sock:/var/run/docker.sock selenium/standalone-docker:4.38.0@sha256:fab923c7b70ee3a1810eb17c3bbd7b6d3596a67d67e29ef30f1d9c980ff3b8e1

Relevant log output

Client: Docker Engine - Community
 Version:           29.0.2
 API version:       1.52
 Go version:        go1.25.4
 Git commit:        8108357
 Built:             Mon Nov 17 12:33:26 2025
 OS/Arch:           linux/amd64
 Context:           default

Server: Docker Engine - Community
 Engine:
  Version:          29.0.2
  API version:      1.52 (minimum version 1.44)
  Go version:       go1.25.4
  Git commit:       e9ff10b
  Built:            Mon Nov 17 12:33:26 2025
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          v2.1.5
  GitCommit:        fcd43222d6b07379a4be9786bda52438f0dd16a1
 runc:
  Version:          1.3.3
  GitCommit:        v1.3.3-0-gd842d771
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

Virtual environment detected at /home/seluser/venv, activating...
Python 3.14.0
2025-11-24 09:07:10,249 INFO Included extra file "/etc/supervisor/conf.d/selenium-grid-docker.conf" during parsing
2025-11-24 09:07:10,252 INFO RPC interface 'supervisor' initialized
2025-11-24 09:07:10,252 INFO supervisord started with pid 10
2025-11-24 09:07:10,253 INFO spawned: 'socat' with pid 11
2025-11-24 09:07:10,254 INFO spawned: 'selenium-grid-docker' with pid 12
2025-11-24 09:07:10,258 INFO success: socat entered RUNNING state, process has stayed up for > than 0 seconds (startsecs)
2025-11-24 09:07:10,258 INFO success: selenium-grid-docker entered RUNNING state, process has stayed up for > than 0 seconds (startsecs)
Starting Selenium Grid Standalone Docker...
Appending Selenium option: --enable-managed-downloads true
Appending Selenium option: --log-level INFO
Appending Selenium option: --http-logs false
Appending Selenium option: --structured-logs false
Selenium Grid Standalone Docker configuration: 
[docker]
# Configs have a mapping between the Docker image to use and the capabilities that need to be matched to
# start a container with the given image.
configs = [
    "selenium/standalone-firefox:4.38.0-20251101", '{"browserName": "firefox", "platformName": "linux"}',
    "selenium/standalone-chrome:4.38.0-20251101", '{"browserName": "chrome", "platformName": "linux"}',
    "selenium/standalone-edge:4.38.0-20251101", '{"browserName": "MicrosoftEdge", "platformName": "linux"}'
    ]
# Share configs of volumes, DNS, extra hosts between node-docker and node browser containers
host-config-keys = ["Dns", "DnsOptions", "DnsSearch", "ExtraHosts", "Binds"]

# URL for connecting to the docker daemon
# host.docker.internal works for macOS and Windows.
# Linux could use --net=host in the `docker run` instruction or 172.17.0.1 in the URI below.
# To have Docker listening through tcp on macOS, install socat and run the following command
# socat -4 TCP-LISTEN:2375,fork UNIX-CONNECT:/var/run/docker.sock
url = "http://127.0.0.1:2375"
# Docker image used for video recording
video-image = "selenium/video:ffmpeg-8.0-20251101"

# Uncomment the following section if you are running the node on a separate VM
# Fill out the placeholders with appropriate values
#[server]
#host = <ip-from-node-machine>
#port = <port-from-node-machine>
Appending Selenium option: --tracing false
Tracing is disabled
Using JAVA_OPTS:  -Dwebdriver.remote.enableTracing=false -Dwebdriver.httpclient.version=HTTP_1_1
09:07:10.538 INFO [LoggingOptions.configureLogEncoding] - Using the system default encoding
09:07:10.540 INFO [LoggingOptions.getTracer] - Using null tracer
09:07:10.859 INFO [LoggingOptions.getTracer] - Using null tracer
09:07:10.865 INFO [NodeOptions.getSessionFactories] - Detected 24 available processors
09:07:11.050 ERROR [Bootstrap.runMain] - Error during execution
java.lang.reflect.InvocationTargetException
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:118)
        at java.base/java.lang.reflect.Method.invoke(Method.java:580)
        at org.openqa.selenium.grid.Bootstrap.runMain(Bootstrap.java:77)
        at org.openqa.selenium.grid.Bootstrap.main(Bootstrap.java:70)
Caused by: org.openqa.selenium.grid.config.ConfigException: java.lang.reflect.InvocationTargetException
        at org.openqa.selenium.grid.config.MemoizedConfig.getClass(MemoizedConfig.java:119)
        at org.openqa.selenium.grid.node.config.NodeOptions.getNode(NodeOptions.java:188)
        at org.openqa.selenium.grid.commands.Standalone.createNode(Standalone.java:260)
        at org.openqa.selenium.grid.commands.Standalone.createHandlers(Standalone.java:219)
        at org.openqa.selenium.grid.TemplateGridServerCommand.asServer(TemplateGridServerCommand.java:48)
        at org.openqa.selenium.grid.commands.Standalone.execute(Standalone.java:246)
        at org.openqa.selenium.grid.TemplateGridCommand.lambda$configure$4(TemplateGridCommand.java:122)
        at org.openqa.selenium.grid.Main.launch(Main.java:83)
        at org.openqa.selenium.grid.Main.go(Main.java:56)
        at org.openqa.selenium.grid.Main.main(Main.java:41)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
        ... 3 more
Caused by: java.lang.reflect.InvocationTargetException
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:118)
        at java.base/java.lang.reflect.Method.invoke(Method.java:580)
        at org.openqa.selenium.grid.config.ClassCreation.callCreateMethod(ClassCreation.java:51)
        at org.openqa.selenium.grid.config.MemoizedConfig.lambda$getClass$4(MemoizedConfig.java:104)
        at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1740)
        at org.openqa.selenium.grid.config.MemoizedConfig.getClass(MemoizedConfig.java:99)
        ... 13 more
Caused by: org.openqa.selenium.docker.DockerException: Unable to reach the Docker daemon at http://127.0.0.1:2375
        at org.openqa.selenium.grid.node.docker.DockerOptions.getDockerSessionFactories(DockerOptions.java:135)
        at org.openqa.selenium.grid.node.local.LocalNodeFactory.create(LocalNodeFactory.java:93)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
        ... 18 more
2025-11-24 09:07:11,386 WARN exited: selenium-grid-docker (exit status 1; not expected)

Operating System

Ubuntu 24.04.3 LTS

Docker Selenium version (image tag)

4.38.0@sha256:fab923c7b70ee3a1810eb17c3bbd7b6d3596a67d67e29ef30f1d9c980ff3b8e1

Selenium Grid chart version (chart version)

No response

[github-actions]

@richard-kramer-work, thank you for creating this issue. We will troubleshoot it as soon as we can.

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Thank you!

[VietND96]

We early detected that breaking change from Docker Engine and fix it in SeleniumHQ/selenium#16591
Dynamic Grid 4.39.0 will be released soon!