DOCKER_HOST environment variable on windows

Question

I'm running Docker 1.12.0 on a Windows 10 machine. I'm developing a Java program, using Maven 3.3.9 as a dependency manager. I have a maven docker plugin ( https://github.com/fabric8io/docker-maven-plugin ), which gives the following error on clean install.

[ERROR] Failed to execute goal io.fabric8:docker-maven-plugin:0.15.16:build (docker-build-start) on project integration-test: Execution docker-build-start of goal io.fabric8:docker-maven-plugin:0.15.16:build failed: No <dockerHost> or <machine> given, no DOCKER_HOST environment variable, and no read/writable '/var/run/docker.sock' -> [Help 1]

When I run a clean install with the following configuration option in the POM file:

<dockerHost>tcp://0.0.0.0:2376</dockerHost>

the following result is shown.

[ERROR] Failed to execute goal io.fabric8:docker-maven-plugin:0.15.16:build (docker-build-start) on project integration-test: Cannot create docker access object: Cannot extract API version from server https://0.0.0.0:2376 : Connect to 0.0.0.0:2376 [/0.0.0.0] failed: Connection refused: connect -> [Help 1]

My question: is there an IP address I can use to tell this maven plugin where it can reach the daemon? Normal docker commands work perfectly fine. The plugin works without any problems on OS X.

Answer 1

On Windows 10 with Docker for Windows, the Docker Engine API is available in these two locations:

• npipe:////./pipe/docker_engine
• http://localhost:2375

I recommend trying with the localhost one.

Details here: https://docs.docker.com/docker-for-windows/faqs/#/how-do-i-connect-to-the-remote-docker-engine-api

Answer 2

It seems the user which is running Maven goals doesn't have access to docker.sock . The error message is telling which options are there to resolve the problem.

No <dockerHost> or <machine> given, no DOCKER_HOST environment variable, and no read/writable '/var/run/docker.sock '

Last option is the easiest one because it requires a file permission and it doesn't need to create any docker machine or set a DOCKER_HOST, On Linux you can change read/write permission of docker.sock with the following:

sudo chmod 776 /var/run/docker.sock

On windows go through this article : Microsoft article

Answer 3

After nearly a day of fruitless Googling I found this solution by myself. Trivial, but might still help others.

You need to enable the checkbox 'Expose daemon on...' under Settings -> General

Answer 4

If someone just wants to skip fabric8 docker-maven-plugin execution that prevents build to succeed with error

No given, no DOCKER_HOST environment variable, no read/writable '/var/run/docker.sock' or '//./pipe/docker_engine' and no external provider like Docker machine configured

then this can be achieved with -Ddocker.skip=true according to https://dmp.fabric8.io/#global-configuration .

Answer 5

If you are using Window and Maven in eclipse to build your java project but continue seeing that error, then you have to perform these steps:

Step1:

You need to enable the checkbox 'Expose daemon on...' under Settings -> General As mentioned by @Adriaan Koster

If step1 does not solve the issue,then

Step2: Run your eclipse in administration mode. Now it should work without issues.

Answer 6

use docker-machine if you are using toolbox.

            <machine>
                <name>default</name>
                <autoCreate>true</autoCreate>
                <createOptions>
                    <driver>virtualbox</driver>
                    <virtualbox-cpu-count>2</virtualbox-cpu-count>
                </createOptions>
            </machine>