1、Docker服务开启TCP端口：

1、服务器开启TCP端口
192.168.43.23 k8s-master
环境：CentOS Linux release 7.8.2003 (Core)

$ vi /lib/systemd/system/docker.service
注释原有的：
#ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
添加新的：
ExecStart=/usr/bin/dockerd -H unix:///var/run/docker.sock -H tcp://0.0.0.0:2375

# 重新加载系统服务配置文件（包含刚刚修改的文件）
$ systemctl daemon-reload

# 重启docker服务
$ systemctl restart docker

# 查看端口是否被docker监听
$ ss -tnl | grep 2375
# 查看端口是否开启
$ netstat -nlpt

# 查看防火墙是否开放2375端口（防火墙未开启则无需开放）
$ firewall-cmd --zone=public --query-port=2375/tcp
# 防火墙添加开放2375端口
$ firewall-cmd --zone=public --add-port=80/tcp --permanent
# 重启防火墙
$ firewall-cmd --reload

# 验证：直接curl看是否生效
$ curl http://127.0.0.1:2375/info
# 虚拟机配置好之后，本机的window上，telnet测试：
$ telnet 192.168.43.23 2375

2、Idea中配置Docker

1）安装 Docker integration 插件
File->Settings->Plugins ，安装后重启idea
2）配置 Docker
File->Settings->Build,Execution,Deployment->Docker
选择 TCP socket，Engine API URL设置为： tcp://192.168.43.23:2375
直到下方出现 Connection successful
3）修改pom文件

  <properties>
    <springboot.version>2.4.2</springboot.version>
    <docker.image.prefix>chenchg</docker.image.prefix>
  </properties>

<build><plugins>
...
    <plugin>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-maven-plugin</artifactId>
      <version>${springboot.version}</version>
      <executions>
        <execution>
          <goals>
            <goal>repackage</goal>
          </goals>
        </execution>
      </executions>
    </plugin>

    <!-- docker -->
    <plugin>
      <groupId>com.spotify</groupId>
      <artifactId>docker-maven-plugin</artifactId>
      <version>0.4.13</version>
      <configuration>
        <!-- made of '[a-z0-9-_.]'  eg: chenchg/dkdemo:1.1.0-->
        <imageName>${docker.image.prefix}/${project.artifactId}:${project.version}</imageName>
        <dockerDirectory>${project.basedir}</dockerDirectory>
        <dockerHost>http://192.168.43.23:2375</dockerHost>
        <resources>
          <resource>
            <targetPath>/</targetPath>
            <directory>${project.build.directory}</directory>
            <include>${project.build.finalName}.jar</include>
          </resource>
        </resources>
      </configuration>
    </plugin>
...
</plugins></build>

4. 项目根目录配置Dockerfile
   根目录对应plugin中的dockerDirectory配置：${project.basedir}
   FROM java:8
   VOLUME /tmp
   COPY target/demo-0.0.1-SNAPSHOT.jar demo.jar
   RUN bash -c “touch /demo.jar”
   EXPOSE 8080
   ENTRYPOINT [“java”,"-jar",“demo.jar”]