How to use remote docker daemon?

[jiangyongbing24]

Environment:

• Jib version: 1.4.13
• Build tool: Maven
• OS: maven app: win10,remote docker daemon: centos7

Description of the issue:
I want to use the remote docker daemon to pull and upload images. The dockerclient Property in the document is configured as a daemon into the local path. If I want to use a remote one, how do I configure it?

[chanseokoh]

Hi @jiangyongbing24

You should be able to pass Docker-specific environment variables like DOCKER_HOST. See #1956 (comment) For example,

jib {
  dockerClient.environment = [ DOCKER_HOST: '...', DOCKER_TLS_VERIFY: '...' ]
}

I have no experience using a remote Docker engine. I wonder if this will help: https://gist.github.com/kekru/4e6d49b4290a4eebc7b597c07eaf61f2#set-env-var-linux-mac-windows I'm curious if this actually works well. Could you update here after trying it?

[chanseokoh]

For Maven, it should be like

<dockerClient>
    <environment>
        <DOCKER_HOST>...</DOCKER_HOST>
    </environment>
</dockerClient>

See https://github.com/GoogleContainerTools/jib/tree/master/jib-maven-plugin#dockerclient-object

[chanseokoh]

This actually works.

1. Run a Docker daemon in Docker; API exposed via port 2375

   $ docker run --rm -p2375:2375 --privileged -e DOCKER_TLS_CERTDIR= docker:19.03.3-dind
   

2. Set DOCKER_HOST to localhost:2375.

   <dockerClient>
       <environment>
           <DOCKER_HOST>localhost:2375</DOCKER_HOST>
       </environment>
   </dockerClient>

3. Build and push an image with Jib.

   $ mvn jib:dockerBuild
   ...
   [INFO] Built image to Docker daemon as francium25/test
   ...
   [INFO] BUILD SUCCESS
   

4. Check the image.

   $ docker inspect francium25/test
   []
   Error: No such object: francium25/test
   $ DOCKER_HOST=localhost:2375 docker inspect francium25/test
   [                                                                                                                                                                                                    
       {                                                                                                                                                                                                
           "Id": "sha256:f174a058dbd3cc99a8996f7a6b654c7bbb0928e44d33ae0d6b027120a6e92e4b",                                                                                                             
   

[swang-harbin]

This is my pom.xml

<project>
    ...
    <properties>
        <!--指定 jib-maven-plugin 插件的版本  -->
        <jib-maven-plugin.version>3.1.4</jib-maven-plugin.version>
    </properties>
    <plugin>
        <groupId>com.google.cloud.tools</groupId>
        <artifactId>jib-maven-plugin</artifactId>
        <version>${jib-maven-plugin.version}</version>
        <configuration>
            <!-- 以哪个镜像作为基本镜像 -->
            <from>
                <image>openjdk:8</image>
            </from>
            <!-- 将该模块部署到哪个仓库 -->
            <to>
                <image>docker.io/swanghub/flowable-test</image>
                <!-- 推荐使用 credHelper 或者将用户名和密码配置在 maven 的 settings.xml 中 -->
                <!--auth>
                        <username>username</username>
                        <password>password</password>
                </auth-->
                <credHelper>wincred</credHelper>
                <tags>
                    <tag>${project.version}</tag>
                    <tag>latest</tag>
                </tags>
            </to>
            <!-- 配置 Docker daemon -->
            <dockerClient>
                <executable>docker</executable>
                <environment>
                    <DOCKER_HOST>http://intelli.icu:2375</DOCKER_HOST>
                </environment>
            </dockerClient>
            <!-- 容器相关属性设置 -->
            <container>
                <!-- 要暴露的端口 -->
                <ports>
                    <port>8080</port>
                </ports>
                <!-- 修改镜像默认时间，否则会出现镜像内时区不正确 -->
                <creationTime>USE_CURRENT_TIMESTAMP</creationTime>
            </container>
            <!-- 允许使用 http 连接 -->
            <allowInsecureRegistries>true</allowInsecureRegistries>
        </configuration>
        <executions>
            <!-- 在执行 mvn deploy 的同时，将项目打包成 docker 镜像并推送到 docker 远程仓库 -->
            <execution>
                <id>push-docker-image-when-maven-deploy</id>
                <phase>deploy</phase>
                <goals>
                    <goal>build</goal>
                </goals>
            </execution>
            <!-- 在执行 mvn package 的同事，将项目打包成 docker 镜像并推动到 Docker daemon -->
            <execution>
                <id>run-docker-image-when-maven-package</id>
                <phase>package</phase>
                <goals>
                    <goal>dockerBuild</goal>
                </goals>
            </execution>
        </executions>
    </plugin>
    ...
</project>

When I run mvn package or jib dockerBuild, it show:

Build to Docker daemon failed, perhaps you should make sure Docker is installed and you have correct privileges to run it

I want to push the image of this java application to the remote docker daemon, and let it run remotely as a container. I don't want to install anything about docker locally.

When I installed the Docker-CLI,it can push the image to the remote docker daemon。Why spotify/dockerfile-maven and fabric8io/docker-maven-plugin don't need Docker-CLI?

[chanseokoh]

@swang-harbin unfortunately for now, Jib requires executing a Docker client (the docker CLI) to communicate to a Docker engine (whether remote or local): #1997

I believe you are already aware of this, but you just need to download and unzip a Docker client (docker); no need for a Docker engine (dockerd). For the spotify and fabric8io plugins, I guess they are using some Docker client Java library instead of running docker.