Java应用打包成Docker镜像

使用docker load

将可运行的jar与dockerfile放在同一个目录，例如：
在这里插入图片描述

dockerfile内容如下：

## 使用最精简的jdk版本
FROM java:8-alpine

## 设置时区
RUN apk add -U tzdata
RUN cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime

## 设置输出格式
ENV LANG en_US.UTF-8
ENV LANGUAGE en_US:en
ENV LC_ALL en_US.UTF-8

## 设置作者
##指定镜像作者信息，即镜像的Author属性
MAINTAINER saleson

## 添加jar 第一个参数是源jar， 第二个参数输出jar
## ADD的用法是：ADD 宿主机文件的全路径 docker容器下的文件夹路径
ADD istio-springboot-demo-a-1.0-SNAPSHOT.jar demo-a-app.jar

## 通知 Docker 容器在运行时监听指定的网络端口.EXPOSE  
##暴露的端口更像是指明了该容器提供的服务需要用到的端口.
##EXPOSE 并不会直接将端口自动和宿主机某个端口建立映射关系
## 如果 docker run，指定了自动映射 -P，那么会将所有暴露的端口随机映射到宿主机的高阶端口
EXPOSE 8080

## 指定镜像的默认入口命令，该入口命令会在启动容器时作为根命令执行
ENTRYPOINT exec java -Xmx32m -Xms32m -Xmn32m -Xss256k -jar demo-a-app.jar

执行docker build命令打包镜像

% docker build -f dockerfile -t istio-springboot-demo-a:latest .
[+] Building 2.6s (9/9) FINISHED
 => [internal] load build definition from dockerfile                                                                                                                            0.0s
 => => transferring dockerfile: 1.22kB                                                                                                                                          0.0s
 => [internal] load .dockerignore                                                                                                                                               0.0s
 => => transferring context: 2B                                                                                                                                                 0.0s
 => [internal] load metadata for docker.io/library/java:8-alpine                                                                                                                2.4s
 => [1/4] FROM docker.io/library/java:8-alpine@sha256:d49bf8c44670834d3dade17f8b84d709e7db47f1887f671a0e098bafa9bae49f                                                          0.0s
 => [internal] load build context                                                                                                                                               0.0s
 => => transferring context: 64B                                                                                                                                                0.0s
 => CACHED [2/4] RUN apk add -U tzdata                                                                                                                                          0.0s
 => CACHED [3/4] RUN cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime                                                                                                        0.0s
 => CACHED [4/4] ADD istio-springboot-demo-a-1.0-SNAPSHOT.jar demo-a-app.jar                                                                                                    0.0s
 => exporting to image                                                                                                                                                          0.0s
 => => exporting layers                                                                                                                                                         0.0s
 => => writing image sha256:5c794ac6ebad9b3b5e581ca642589ad3aa9ff96bf3e53883e31168e39ff52bd0                                                                                    0.0s
 => => naming to docker.io/library/istio-sb-demo-a                                                                                                                              0.0s

Use 'docker scan' to run Snyk tests against images to find vulnerabilities and learn how to fix them

% docker images
REPOSITORY                                                TAG                                                                          IMAGE ID       CREATED          SIZE
istio-sb-demo-a                                           latest                                                                       5c794ac6ebad   2 minutes ago   166MB

maven 打包docker镜像

如果有parent，且要打包的是sub module，需要先在parent的pom.xml添加plugin:

<build>
    <pluginManagement>
        <plugins>
            <plugin>
                <groupId>com.spotify</groupId>
                <artifactId>docker-maven-plugin</artifactId>
                <version>1.2.2</version>
            </plugin>
        </plugins>
    </pluginManagement>
</build>

不然会运行 mvn clean package docker:build 会maven 会提示 No plugin found for prefix ‘docker’ in the current project
如下:

[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.948 s
[INFO] Finished at: 2022-07-21T17:24:01+08:00
[INFO] Final Memory: 13M/54M
[INFO] ------------------------------------------------------------------------
[ERROR] No plugin found for prefix 'docker' in the current project and in the plugin groups [org.apache.maven.plugins, org.codehaus.mojo] available from the repositories [local (/Users/saleson/.m2/repository), nexus-aliyun (http://maven.aliyun.com/nexus/content/groups/public)] -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/NoPluginFoundForPrefixException

在sub module的pom.xml中添加docker-maven-plugin

    <build>
    	<plugins>
    		<defaultGoal>spring-boot:run</defaultGoal>
        	<plugin>
        		// spring-boot-maven-plugin
        	</plugin>
            <!-- 打包到 docker 服务-->
            <plugin>
                <groupId>com.spotify</groupId>
                <artifactId>docker-maven-plugin</artifactId>
                <configuration>
                    <imageName>${project.artifactId}:latest</imageName>
                    <!-- Dockerfile的地址 -->
                    <dockerDirectory>${project.basedir}/docker</dockerDirectory>
                    <resources>
                        <resource>
                            <targetPath>/</targetPath>
                            <directory>${project.build.directory}</directory>
                            <include>${project.build.finalName}.jar</include>
                        </resource>
                    </resources>
                </configuration>
            </plugin>
        </plugins>
    </build>

在sub module 下新增dockerfile, 路径: docker/Dockerfile
在这里插入图片描述

Dockerfile 内容如下：

FROM java:8-alpine
## 设置时区
RUN apk add -U tzdata
RUN cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
## 设置输出格式
ENV LANG en_US.UTF-8
ENV LANGUAGE en_US:en
ENV LC_ALL en_US.UTF-8

MAINTAINER saleson
ADD istio-springboot-demo-a-1.0-SNAPSHOT.jar demo-a-app.jar
EXPOSE 8080
ENTRYPOINT exec java -Xmx32m -Xms32m -Xmn32m -Xss256k -jar demo-a-app.jar --spring.profiles.active=dev

运行mvn 命令执行打包：

mvn clean package docker:build -DskipTests

查看打包后的镜像

% docker images
REPOSITORY                                                TAG                                                                          IMAGE ID       CREATED         SIZE
istio-springboot-demo-a                                   latest                                                                       22f5d43a2563   6 seconds ago   166MB

maven 无dockerfile

所有的docker 打包配置都放在maven plugin的configuration中，配置如下：

<!-- 打包到 docker 服务-->
            <plugin>
                <groupId>com.spotify</groupId>
                <artifactId>docker-maven-plugin</artifactId>
                <!--将插件绑定在某个phase执行-->
                <executions>
                    <execution>
                        <id>build-image</id>
                        <!--用户只需执行mvn package ，就会自动执行mvn docker:build-->
                        <phase>package</phase>
                        <goals>
                            <goal>build</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <!--指定生成的镜像名,这里是我们的作者名+项目名-->
                    <imageName>demo-${project.artifactId}:${docker.image.version}</imageName>
                    <!--指定标签 这里指定的是镜像的版本，我们默认版本是latest-->
<!--                    <imageTags>-->
<!--                        <imageTag>latest</imageTag>-->
<!--                    </imageTags>-->
                    <!--指定基础镜像jdk1.8-->
                    <baseImage>java:8-alpine</baseImage>
                    <!--
                    镜像制作人本人信息-->
                    <maintainer>saleson</maintainer>
                    <!--切换到ROOT目录-->
<!--                    <workdir>/ROOT</workdir> -->
                    <!--查看我们的java版本-->
<!--                    <cmd>["java", "-version"]</cmd>-->
                    <!--${project.build.finalName}.jar是打包后生成的jar包的名字-->
                    <runs>
                        <run>apk add -U tzdata</run>
                        <run>cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime</run>
                    </runs>
                    <env>
                    </env>
                    <env>
                        <LANG>en_US.UTF-8</LANG>
                        <LANGUAGE>en_US:en</LANGUAGE>
                        <LC_ALL>en_US.UTF-8</LC_ALL>
                    </env>
                    <labels>
                        <label>usage=istio-demo</label>
                    </labels>
                    <entryPoint>exec java -Xmx32m -Xms32m -Xmn32m -Xss256k -jar ${project.build.finalName}.jar --spring.profiles.active=dev</entryPoint>
                    <exposes>
                        <expose>8082</expose>
                    </exposes>
                    <!--指定远程 docker api地址-->
<!--                    <dockerHost>http://localhost:2375</dockerHost>-->
                    <!-- 这里是复制 jar 包到 docker 容器指定目录配置 -->
                    <resources>
                        <resource>
                            <targetPath>/</targetPath>
                            <!--jar 包所在的路径  此处配置的 即对应 target 目录-->
                            <directory>${project.build.directory}</directory>
                            <!--用于指定需要复制的文件 需要包含的 jar包 ，这里对应的是 Dockerfile中添加的文件名　-->
                            <include>${project.build.finalName}.jar</include>
                        </resource>
                    </resources>
                </configuration>
            </plugin>

运行docker 镜像

使用docker run 命令运行镜像，如下：

% docker run -d -p 8080:8080 --name istio-springboot-demo-a istio-springboot-demo-a:latest
1855aa699105703ad83e2f7332a4c6fe2f1a0e1fd51ebe4017e7cc2058cf773e

查看pod运行情况：

% docker ps -a
CONTAINER ID   IMAGE                            COMMAND                  CREATED          STATUS          PORTS                    NAMES
8bec7d566384   istio-springboot-demo-a:latest   "/bin/sh -c 'exec ja…"   5 seconds ago    Up 3 seconds    0.0.0.0:8080->8080/tcp   istio-springboot-demo-a

参考

dockerfile ENTRYPOINT

Java应用打包成Docker镜像

使用docker load

maven 打包docker镜像

maven 无dockerfile

运行docker 镜像

参考

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