Can't connect to the docker daemon while running Maven jib plugin in Gitlab CI

Question

I'm trying to build a docker image with my application in Gitlab continuous integration using the jib Maven plugin, but I can't get the plugin connect to the docker daemon using the dind (docker-in-docker) service. Currently I'm using this configuration in my gitlab-ci.yml file:

deploy:mvn:
  image: maven:3.6.3-jdk-8-openj9
  stage: deploy
  services:
    - docker:dind
  script:
    - mvn compile jib:dockerBuild

This is the error I get:

[ERROR] Failed to execute goal com.google.cloud.tools:jib-maven-plugin:0.9.11:dockerBuild (default-cli) on project my-application: Build to Docker daemon failed, perhaps you should make sure Docker is installed and you have correct privileges to run it -> [Help 1]

---

UPDATE

I updated to 2.2.0 and it's running locally. I added the docker images command before and the plugin seems not to be able to find the docker command in Gitlab CI:

$ docker images && mvn compile jib:dockerBuild /bin/bash: line 97: docker: command not found

This is the configuration for the jib plugin:

<plugin>
    <groupId>com.google.cloud.tools</groupId>
    <artifactId>jib-maven-plugin</artifactId>
    <version>2.2.0</version>
    <configuration>
        <from>
            <image>adoptopenjdk/openjdk11:alpine-jre</image>
        </from>
        <to>
            <image>my-application:latest</image>
        </to>
        <container>
            <entrypoint>
                <shell>sh</shell>
                <option>-c</option>
                <arg>chmod +x /entrypoint.sh &amp;&amp; sync &amp;&amp; /entrypoint.sh</arg>
            </entrypoint>
            <ports>
                <port>8080</port>
            </ports>
            <environment>
                <SPRING_OUTPUT_ANSI_ENABLED>ALWAYS</SPRING_OUTPUT_ANSI_ENABLED>
                <JHIPSTER_SLEEP>0</JHIPSTER_SLEEP>
            </environment>
            <creationTime>USE_CURRENT_TIMESTAMP</creationTime>
        </container>
    </configuration>
</plugin>

Answer 1

the plugin seems not to be able to find the docker command in Gitlab CI:

No, it is not Jib but /bin/bash that cannot find the docker command. Even before using Jib, you don't have docker available. Take a closer look at the error message.

$ docker images && mvn compile jib:dockerBuild /bin/bash: line 97: docker: command not found

For example, on my Linux, if I try a command foo that doesn't exist in a shell script, it outputs the same message.

$ /bin/bash -c "foo && mvn -v"
/bin/bash: line 1: foo: command not found

Therefore, the following command without mvn will fail with the same error.

script:
  - docker images

This proves that either docker doesn't exist in your GitLab runtime environment or is not on the PATH environment variable.

---

UPDATE

Updating my answer, since you answered that you now use jib:build instead of jib:dockerBuild.

If you use jib:build, you don't even need Docker. Jib doesn't require Docker when building and pushing an image to a remote registry with jib:build. Therefore, you can completely forget about setting up Docker and remove docker:dind and export DOCKER_HOST:

mvn compile jib:build -Djib.to.auth.username=$DOCKER_REGISTRY_USER -Djib.to.auth.password=$DOCKER_REGISTRY_PWD

Answer 2

Finally this is the configuration I got it working with:

services:
    - docker:dind


deploy:mvn:
    image: maven:3.6.3-jdk-8-openj9
    stage: deploy
    script:
        - export DOCKER_HOST=tcp://docker:2375
        - mvn compile jib:build -Djib.to.auth.username=$DOCKER_REGISTRY_USER -Djib.to.auth.password=$DOCKER_REGISTRY_PWD
    only:
        - tags

Apart from using the Docker in Docker service I needed to establish the DOCKER_HOST environment variable and also pass the credentials to my mvn jib:build command. I stored the credentials in CI settings, as environment variables. Thanks @Chanseok Oh for your help.

See also:

• Using docker build
• Jib docs