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本文链接:[https://blog.csdn.net/boling\_cavalry/article/details/100179709](https://blog.csdn.net/boling_cavalry/article/details/100179709)
近期在用Jib插件将Java工程构建成Docker镜像,使用时遇到过一些小问题,今天对这些问题做个小结;
Jib是用于构建Docker镜像的Maven插件,其基本用法请参考《Docker与Jib(maven插件版)实战》一文;
本文由以下几部分组成:
本次实战用到的源码是个简单的maven工程,可以从GitHub上下载本次实战的源码,地址和链接信息如下表所示:
名称 | 链接 | 备注 |
---|---|---|
项目主页 | 该项目在GitHub上的主页 | |
git仓库地址(https) | 该项目源码的仓库地址,https协议 | |
git仓库地址(ssh) | git@github.com:zq2599/blog_demos.git | 该项目源码的仓库地址,ssh协议 |
这个git项目中有多个文件夹,本章的源码在hellojib文件夹下,如下图红框所示:
对于一个已在pom.xml中配置了jib插件的java工程来说,下面是个标准的构建命令:
mvn compile jib:dockerBuild
注意上面的dockerBuild参数,该参数的意思是将镜像存入当前的镜像仓库,这样的参数一共有三种,列表说明:
参数名 | 作用 |
---|---|
dockerBuild | 将镜像存入当前镜像仓库,该仓库是当前docker客户端可以连接的docker daemon,一般是指本地镜像仓库 |
build | 将镜像推送到远程仓库,仓库位置与镜像名字的前缀有关,一般是hub.docker.com,使用该参数时需要提前登录成功 |
buildTar | 将镜像生成tar文件,保存在项目的target目录下,在任何docker环境执行 docker load --input xxx.tar即可导入到本地镜像仓库 |
在使用命令mvn compile jib:dockerBuild构建本地镜像时,会遇到创建时间不准的问题:
如下所示,bolingcavalry/hellojib是刚刚使用jib插件构建的镜像,其生成时间(CREATED字段)显示的是49 years ago:
[root@maven hellojib]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
bolingcavalry/hellojib 0.0.1-SNAPSHOT ef96fdd4473a 49 years ago 505 MB
上面显示的镜像生成时间显然是不对的,改正此问题的方法是修改pom.xml,在jib插件的container节点内增加useCurrentTimestamp节点,内容是true,如下所示:
<plugin>
<groupId>com.google.cloud.tools</groupId>
<artifactId>jib-maven-plugin</artifactId>
<version>1.3.0</version>
<configuration>
<!--from节点用来设置镜像的基础镜像,相当于Docerkfile中的FROM关键字-->
<from>
<!--使用openjdk官方镜像,tag是8-jdk-stretch,表示镜像的操作系统是debian9,装好了jdk8-->
<image>openjdk:8u212-jdk-stretch</image>
</from>
<to>
<!--镜像名称和tag,使用了mvn内置变量${project.version},表示当前工程的version-->
<image>bolingcavalry/hellojib:${project.version}</image>
</to>
<!--容器相关的属性-->
<container>
<!--jvm内存参数-->
<jvmFlags>
<jvmFlag>-Xms4g</jvmFlag>
<jvmFlag>-Xmx4g</jvmFlag>
</jvmFlags>
<!--要暴露的端口-->
<ports>
<port>8080</port>
</ports>
<!--使用该参数将镜像的创建时间与系统时间对其-->
<useCurrentTimestamp>true</useCurrentTimestamp>
</container>
</configuration>
</plugin>
修改保存后再次构建,此时新的镜像的创建时间已经正确,显示15 seconds ago:
[root@maven hellojib]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
bolingcavalry/hellojib 0.0.1-SNAPSHOT ee5ba19a8016 23 seconds ago 505 MB
<none> <none> ef96fdd4473a 49 years ago 505 MB
如下所示,构建多次后,本地会遗留多个名为<none>,tag也是<none>的镜像:
[root@maven hellojib]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
bolingcavalry/hellojib 0.0.1-SNAPSHOT a9fd91d8ad8c 17 seconds ago 505 MB
<none> <none> a0cadeb9febd About a minute ago 505 MB
<none> <none> ee5ba19a8016 2 minutes ago 505 MB
<none> <none> ef96fdd4473a 49 years ago 505 MB
这些都是上一次构建的结果,在经历了新一轮的构建后,其镜像名和tag被新镜像所有,所以自身只能显示名为<none>,tag也是<none>,清理这些镜像的命令是docker image prune,然后根据提示输入"y",镜像即可被清理:
[root@maven hellojib]# docker image prune
WARNING! This will remove all dangling images.
Are you sure you want to continue? [y/N] y
Deleted Images:
deleted: sha256:7aa104e20b8a08bac3255f2627ac90f10021c6630370ce7a84ba33f89404b153
deleted: sha256:7dd7376ae00c2df0411bac1eded4b3c79dd1528f5711057fe11a4f4121504486
deleted: sha256:e71ced47e80a7fccfea1710f1e5a257d4e16fc3e96b05616007e15829e71a7b2
deleted: sha256:55bed58453479c2accfc08fabc929aece7d324af0df94335dd46333db9da1d23
deleted: sha256:ef96fdd4473a7ca9d39a50e0feae50131de083cee4f11060ad8bee1bc853b2b5
Total reclaimed space: 0 B
[root@maven hellojib]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
bolingcavalry/hellojib 0.0.1-SNAPSHOT 3afd4165b6b6 About a minute ago 505 MB
在使用命令mvn compile jib:dockerBuild构建本地镜像时,每次构建的过程中都会提示以下信息:
[INFO] Containerizing application to Docker daemon as bolingcavalry/hellojib:0.0.1-SNAPSHOT...
[INFO] The base image requires auth. Trying again for openjdk:8-jdk-stretch...
[INFO] Executing tasks:
[INFO] [========= ] 30.0% complete
[INFO] > pulling base image manifest
每次构建都会显示上面的内容,也就是说每次都去远程拉取base镜像的manifest(pulling base image manifest),这部分时间导致整体构架时间变长,以下是构建结果,可见用了10秒:
[INFO] Built image to Docker daemon as bolingcavalry/hellojib:0.0.1-SNAPSHOT
[INFO] Executing tasks:
[INFO] [==============================] 100.0% complete
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 10.722 s
[INFO] Finished at: 2019-09-01T08:55:09+08:00
[INFO] ------------------------------------------------------------------------
首先想到的是执行命令docker pull openjdk:8-jdk-stretch将base镜像下载到本地仓库,再尝试构建,遗憾的是jib依旧会远程获取base镜像的manifest,还是很慢;
如果能避免远程拉取base镜像的manifest,镜像构建速度应该会快一些;基于此推论,优化构建速度的步骤如下:
接下按照上述步骤进行操作:
systemctl restart docker
docker run --name docker-registry -d -p 5000:5000 registry
docker tag 08ded5f856cc 192.168.121.131:5000/openjdk:8-jdk-stretch
[root@maven hellojib]# docker tag 08ded5f856cc 192.168.121.131:5000/openjdk:8-jdk-stretch
[root@maven hellojib]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
bolingcavalry/hellojib 0.0.1-SNAPSHOT 6601ef5a767d 3 minutes ago 505 MB
192.168.121.131:5000/openjdk 8-jdk-stretch 08ded5f856cc 2 weeks ago 488 MB
docker.io/openjdk 8-jdk-stretch 08ded5f856cc 2 weeks ago 488 MB
docker push 192.168.121.131:5000/openjdk:8-jdk-stretch
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<!--使用jib插件-->
<plugin>
<groupId>com.google.cloud.tools</groupId>
<artifactId>jib-maven-plugin</artifactId>
<version>1.3.0</version>
<configuration>
<!--from节点用来设置镜像的基础镜像,相当于Docerkfile中的FROM关键字-->
<from>
<!--使用openjdk官方镜像,tag是8-jdk-stretch,表示镜像的操作系统是debian9,装好了jdk8-->
<image>192.168.121.131:5000/openjdk:8-jdk-stretch</image>
</from>
<to>
<!--镜像名称和tag,使用了mvn内置变量${project.version},表示当前工程的version-->
<image>bolingcavalry/hellojib:${project.version}</image>
</to>
<!--容器相关的属性-->
<container>
<!--jvm内存参数-->
<jvmFlags>
<jvmFlag>-Xms4g</jvmFlag>
<jvmFlag>-Xmx4g</jvmFlag>
</jvmFlags>
<!--要暴露的端口-->
<ports>
<port>8080</port>
</ports>
<useCurrentTimestamp>true</useCurrentTimestamp>
</container>
<allowInsecureRegistries>true</allowInsecureRegistries>
</configuration>
</plugin>
</plugins>
[INFO] Built image to Docker daemon as bolingcavalry/hellojib:0.0.1-SNAPSHOT
[INFO] Executing tasks:
[INFO] [==============================] 100.0% complete
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.949 s
[INFO] Finished at: 2019-09-01T10:51:50+08:00
[INFO] ------------------------------------------------------------------------
以上就是通过registry服务提升jib构建速度的方法,在多人开发的时候,registry可以配置为一个公共的,多人都可使用,毕竟pom.xml代码存在公共代码仓库,每个人都去修改成自己的registry的地址是不合适的,一旦提交上去会影响其他人的使用,我们这里的做法是将registry的地址写成host,本地维护好host和IP的映射就可以了。
使用本地registry服务,除了提速,在服务器无法连接中央仓库取得openjdk:8-jdk-stretch的manifest时,这种方式能保证构建依旧能够成功;
<plugin>
<groupId>com.google.cloud.tools</groupId>
<artifactId>jib-maven-plugin</artifactId>
<version>1.3.0</version>
<configuration>
<!--from节点用来设置镜像的基础镜像,相当于Docerkfile中的FROM关键字-->
<from>
<!--使用openjdk官方镜像,tag是8-jdk-stretch,表示镜像的操作系统是debian9,装好了jdk8-->
<image>192.168.121.131:5000/openjdk:8-jdk-stretch</image>
</from>
<to>
<!--镜像名称和tag,使用了mvn内置变量${project.version},表示当前工程的version-->
<image>bolingcavalry/hellojib:${project.version}</image>
</to>
<!--容器相关的属性-->
<container>
<!--jvm内存参数-->
<jvmFlags>
<jvmFlag>-Xms4g</jvmFlag>
<jvmFlag>-Xmx4g</jvmFlag>
</jvmFlags>
<!--要暴露的端口-->
<ports>
<port>8080</port>
</ports>
<useCurrentTimestamp>true</useCurrentTimestamp>
</container>
<allowInsecureRegistries>true</allowInsecureRegistries>
</configuration>
<executions>
<execution>
<phase>compile</phase>
<goals>
<goal>dockerBuild</goal>
</goals>
</execution>
</executions>
</plugin>
[root@maven hellojib]# mvn compile -DskipTests
[INFO] Scanning for projects...
[INFO]
[INFO] ---------------------< com.bolingcavalry:hellojib >---------------------
[INFO] Building hellojib 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-resources-plugin:3.1.0:resources (default-resources) @ hellojib ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 1 resource
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ hellojib ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- jib-maven-plugin:1.3.0:dockerBuild (default) @ hellojib ---
[WARNING] Setting image creation time to current time; your image may not be reproducible.
[INFO]
[INFO] Containerizing application to Docker daemon as bolingcavalry/hellojib:0.0.1-SNAPSHOT...
[INFO]
[INFO] Container entrypoint set to [java, -Xms4g, -Xmx4g, -cp, /app/resources:/app/classes:/app/libs/*, com.bolingcavalry.hellojib.HellojibApplication]
[INFO]
[INFO] Built image to Docker daemon as bolingcavalry/hellojib:0.0.1-SNAPSHOT
[INFO] Executing tasks:
[INFO] [==============================] 100.0% complete
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.721 s
[INFO] Finished at: 2019-09-01T11:43:23+08:00
[INFO] ------------------------------------------------------------------------
[root@maven hellojib]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
bolingcavalry/hellojib 0.0.1-SNAPSHOT 5e3f62d13a73 35 seconds ago 505 MB
192.168.121.131:5000/openjdk 8-jdk-stretch 08ded5f856cc 2 weeks ago 488 MB
docker.io/openjdk 8-jdk-stretch 08ded5f856cc 2 weeks ago 488 MB
docker.io/registry latest f32a97de94e1 5 months ago 25.8 MB
以上就是我在近期使用Jib插件时遇到的问题小结,希望这些小技巧可以给您提供一些参考,助您解决问题;