Slim-Docker-Image
导读
在容器化实践中部署spring boot应用普遍采用基础java镜像再添加jar包层来构建应用镜像制品。随着公司业务大量上云，每个变更日上传到云上镜像日渐增多，导致本地机房到云上带宽压力倍增。为解决镜像上传问题，调研了相关技术栈决定采用spring boot 2.3新增的镜像分层构建功能。
基础环境
- spring boot version >= 2.3
- java oracle jdk 8u201
- docker version 20.10.13
基于传统单个jar包构建模式
基础Dockerfile
以下是我们基于基础镜像构建spring boot镜像制品的Dockerfile，采用了比较传统的COPY jar包。相信这也是大家普遍采用的模式。Dockefile如下， 该Dockerfile存在一个坑，会在下边阐述。
FROM registry.xxx.com/base/oracle-jdk:8u201
ENV TZ=Asia/Shanghai
ENV LC_ALL en_US.utf8
WORKDIR /app
ADD ./xxx-1.0.0.jar /app/lib/xxx-1.0.0.jar
ADD ./entrypoint.sh /app/bin/entrypoint.sh
ENTRYPOINT exec bash /app/bin/entrypoint.sh
RUN ln -s /app/logs /app/log && chown 1001.1001 -R /app
Base镜像信息
我们base镜像主要分三层添加了相关常用的工具如telnet netstat等以及安全修复
docker image inspect registry.xxx.com/base/oracle-jdk:8u201
分层信息：
"RootFS": {
"Type": "layers",
"Layers": [
"sha256:174f5685490326fc0a1c0f5570b8663732189b327007e47ff13d2ca59673db02",
"sha256:2105884a1756425b2188084cc1738d6a6b13293773af56f6727af1be979858ed",
"sha256:c33745b350978d855171c996779055195b09e227844b7a03a1d795aee803dbb9"
]
}
Base镜像大小 622MB
镜像大小 622MB 不算太小，对比友商有些基础镜像竟然1-2G😂 简直有点离谱。
registry.xxx.com/base/oracle-jdk 8u201 1869b73a8999 2 years ago 622MB
Base镜像history信息
从构建历史可以看出占用空间主要分为三层分别是
- centos 7 基础镜像层
- yum install 层
- jdk 层
docker image history registry.xxx.com/base/oracle-jdk:8u201
IMAGE CREATED CREATED BY SIZE COMMENT
1869b73a8999 2 years ago /bin/sh -c set -ex; cd /tmp; curl -fsSLO… 302MB
<missing> 2 years ago /bin/sh -c #(nop) ENV JAVA_VERSION=8 JAVA_U… 0B
<missing> 2 years ago /bin/sh -c #(nop) ENV TZ=Asia/Shanghai LANG… 0B
<missing> 2 years ago /bin/sh -c set -ex; yum update -y; yum i… 116MB
<missing> 2 years ago /bin/sh -c #(nop) LABEL maintainer=… 0B
<missing> 2 years ago /bin/sh -c #(nop) CMD ["/bin/bash"] 0B
<missing> 2 years ago /bin/sh -c #(nop) LABEL org.label-schema.sc… 0B
<missing> 2 years ago /bin/sh -c #(nop) ADD file:b3ebbe8bd304723d4… 204MB
传统构建方式
docker build -t registry.xxx.com/layer/build:old .
Sending build context to Docker daemon 67.45MB
Step 1/8 : FROM registry.xxx.com/base/oracle-jdk:8u201
---> 1869b73a8999
Step 2/8 : ENV TZ=Asia/Shanghai
---> Running in a67423d7246b
Removing intermediate container a67423d7246b
---> 9304102c278e
Step 3/8 : ENV LC_ALL en_US.utf8
---> Running in 05bf14c10efd
Removing intermediate container 05bf14c10efd
---> 63fb6c823893
Step 4/8 : WORKDIR /app
---> Running in 095764328d18
Removing intermediate container 095764328d18
---> c057ab4a7d18
Step 5/8 : ADD ./xxx-1.0.0.jar /app/lib/xxx-1.0.0.jar
---> 08928447fafa
Step 6/8 : ADD ./entrypoint.sh /app/bin/entrypoint.sh
---> 0902efa62157
Step 7/8 : ENTRYPOINT exec bash /app/bin/entrypoint.sh
---> Running in dc0eb814cfff
Removing intermediate container dc0eb814cfff
---> 20679a170252
Step 8/8 : RUN ln -s /app/logs /app/log && chown 1001.1001 -R /app
---> Running in 34159dca7464
Removing intermediate container 34159dca7464
---> b6043465c072
Successfully built b6043465c072
Successfully tagged registry.xxx.com/layer/build:old
构建后镜像大小 为基础镜像大小 622MB + 2*65M <= 757MB
构建后比我们预期的 jar包加基础镜像所占用的空间大😢 why?
#jar包大小
ls -lh xxx-1.0.0.jar
-rw------- 1 root root 65M Aug 16 10:33 xxx-1.0.0.jar
#镜像大小
docker image ls |grep registry.xxx.com/layer/build
registry.xxx.com/layer/build old b6043465c072 59 seconds ago 757MB
成品构建history信息
查看构建成品的镜像层发现竟然有两层一样大小，也会被推送了两遍。🥲离大谱。通过分析Dockerfile是因为RUN ln -s /app/logs /app/log && chown 1001.1001 -R /app 导致的。为保证镜像安全，生产环境运行统一采用了1001账号运行。为了保证1001对workdir有绝对的读写权限。对目录递归授权导致文件属性发生改变。在构建时认为文件发生变化产生一样大小的两层导致的。（这还是我自己当时优化引入的屎山😊）具体原因我也不太清楚docker构建时如何判定文件发生变化，我原本以为是基于MD5码。实际上在对文件属主属组改变时MD5码是不对变的。有知道的大神可以在评论区留言交流。
docker image history registry.xxx.com/layer/build:old
IMAGE CREATED CREATED BY SIZE COMMENT
b6043465c072 6 minutes ago /bin/sh -c ln -s /app/logs /app/log && chown… 67.4MB
20679a170252 6 minutes ago /bin/sh -c #(nop) ENTRYPOINT ["/bin/sh" "-c… 0B
0902efa62157 6 minutes ago /bin/sh -c #(nop) ADD file:9ac19caf793524884… 128B
08928447fafa 6 minutes ago /bin/sh -c #(nop) ADD file:c7624c195e7c047ee… 67.4MB
c057ab4a7d18 6 minutes ago /bin/sh -c #(nop) WORKDIR /app 0B
63fb6c823893 6 minutes ago /bin/sh -c #(nop) ENV LC_ALL=en_US.utf8 0B
9304102c278e 6 minutes ago /bin/sh -c #(nop) ENV TZ=Asia/Shanghai 0B
1869b73a8999 2 years ago /bin/sh -c set -ex; cd /tmp; curl -fsSLO… 302MB
<missing> 2 years ago /bin/sh -c #(nop) ENV JAVA_VERSION=8 JAVA_U… 0B
<missing> 2 years ago /bin/sh -c #(nop) ENV TZ=Asia/Shanghai LANG… 0B
<missing> 2 years ago /bin/sh -c set -ex; yum update -y; yum i… 116MB
<missing> 2 years ago /bin/sh -c #(nop) LABEL maintainer=currycan… 0B
<missing> 2 years ago /bin/sh -c #(nop) CMD ["/bin/bash"] 0B
<missing> 2 years ago /bin/sh -c #(nop) LABEL org.label-schema.sc… 0B
<missing> 2 years ago /bin/sh -c #(nop) ADD file:b3ebbe8bd304723d4… 204MB
#镜像也推送了两层一样大小
[root@localhost old-nochown]# docker push registry.xxx.com/layer/build:old
The push refers to repository [registry.xxx.com/layer/build]
bb35157fcb0b: Pushing [=============> ] 18.35MB/67.45MB
3c0641004863: Pushed
6ed0abaff975: Pushing [=====================> ] 28.38MB/67.45MB
aa0794231b2c: Pushed
c33745b35097: Layer already exists
2105884a1756: Layer already exists
174f56854903: Layer already exists
优化Dockerfile
原因知道了。优化思路是先创建目录并递归授权。同时构建出来的jar的权限可以通过COPY 指定1001属主属组。
FROM registry.xxx.com/base/oracle-jdk:8u201
ENV TZ=Asia/Shanghai
ENV LC_ALL en_US.utf8
RUN mkdir -pv /app/{bin,lib,logs} && ln -s /app/logs /app/log && chown 1001:1001 -R /app
WORKDIR /app
COPY --chown=1001:1001 ./xxx-1.0.0.jar /app/lib/xxx-1.0.0.jar
COPY --chown=1001:1001 ./entrypoint.sh /app/bin/entrypoint.sh
ENTRYPOINT exec bash /app/bin/entrypoint.sh
优化后的镜像只有COPY这一层的jar包了。
docker image history registry.xxx.com/layer/build:old-mkdir
IMAGE CREATED CREATED BY SIZE COMMENT
b9fc3a8a97f2 29 hours ago /bin/sh -c #(nop) ENTRYPOINT ["/bin/sh" "-c… 0B
c823448f9582 29 hours ago /bin/sh -c #(nop) COPY --chown=1001:1001file… 128B
9a997f3962bf 29 hours ago /bin/sh -c #(nop) COPY --chown=1001:1001file… 67.4MB
f272c4e64f87 29 hours ago /bin/sh -c #(nop) WORKDIR /app 0B
1a526d3df7c2 29 hours ago /bin/sh -c mkdir -pv /app/{bin,lib,logs} && … 9B
63fb6c823893 30 hours ago /bin/sh -c #(nop) ENV LC_ALL=en_US.utf8 0B
9304102c278e 30 hours ago /bin/sh -c #(nop) ENV TZ=Asia/Shanghai 0B
1869b73a8999 2 years ago /bin/sh -c set -ex; cd /tmp; curl -fsSLO… 302MB
<missing> 2 years ago /bin/sh -c #(nop) ENV JAVA_VERSION=8 JAVA_U… 0B
<missing> 2 years ago /bin/sh -c #(nop) ENV TZ=Asia/Shanghai LANG… 0B
<missing> 2 years ago /bin/sh -c set -ex; yum update -y; yum i… 116MB
<missing> 2 years ago /bin/sh -c #(nop) LABEL maintainer=currycan… 0B
<missing> 2 years ago /bin/sh -c #(nop) CMD ["/bin/bash"] 0B
<missing> 2 years ago /bin/sh -c #(nop) LABEL org.label-schema.sc… 0B
<missing> 2 years ago /bin/sh -c #(nop) ADD file:b3ebbe8bd304723d4… 204MB
基于spring boot 分层构建方式
探索基于分层构建原理
直接上手官方文档的demo 把官方文档demo的多阶段构建拆分一下。
cat Dockerfile
FROM registry.xxx.com/base/oracle-jdk:8u201 as builder
WORKDIR /app
COPY --chown=1001:1001 ./xxx-1.0.0.jar /app/lib/xxx-1.0.0.jar
RUN java -Djarmode=layertools -jar /app/lib/xxx-1.0.0.jar extract
一阶段实际就是将jar解压按照spring boot layers.idx文件中的分层方式将依赖和业务代码分层。
- "dependencies":
- BOOT-INF/lib/library1.jar
- BOOT-INF/lib/library2.jar
- "spring-boot-loader":
- org/springframework/boot/loader/JarLauncher.class
- org/springframework/boot/loader/jar/JarEntry.class
- "snapshot-dependencies":
- BOOT-INF/lib/library3-SNAPSHOT.jar
- "application":
- META-INF/MANIFEST.MF
- BOOT-INF/classes/a/b/C.class
进入到容器中可以看到被解压为4个目录：
[root@b762a63589c1 app]# ls
application dependencies lib logs snapshot-dependencies spring-boot-loader
存储占用如下：其中不出意外dependencies也就是依赖库占用是最大的 业务代码只有可怜的304K🤔。
[root@29d87aaf64b9 app]# du -lh --max-depth=1
304K ./application
65M ./dependencies
0 ./logs
20K ./snapshot-dependencies
420K ./spring-boot-loader
65M ./lib
130M .
基于分层构建构建制品镜像
在官方的demo上修改得到完整的Dockerfile。其中优化了entrypoint脚本，采用分层构建后启动应用不能采用传统的java $JAVA_OPTS -jar xxx.jar这方式启动应用。要使用java org.springframework.boot.loader.JarLauncher启动应用因此jvm参数需要通过脚本接受容器的环境变量来传入。
FROM registry.xxx.com/base/oracle-jdk:8u201 as builder
WORKDIR /app
COPY --chown=1001:1001 ./xxx-1.0.0.jar /app/lib/xxx-1.0.0.jar
RUN java -Djarmode=layertools -jar /app/lib/xxx-1.0.0.jar extract
FROM registry.xxx.com/base/oracle-jdk:8u201
ENV TZ=Asia/Shanghai
ENV LC_ALL en_US.utf8
RUN mkdir -pv /app/logs && ln -s /app/logs /app/log && chown 1001:1001 -R /app
WORKDIR /app
COPY --chown=1001:1001 --from=builder /app/dependencies/ ./
COPY --chown=1001:1001 --from=builder /app/spring-boot-loader/ ./
COPY --chown=1001:1001 --from=builder /app/snapshot-dependencies/ ./
COPY --chown=1001:1001 --from=builder /app/application/ ./
CMD ["exec"]
ENTRYPOINT ["bash","/app/entrypoint.sh"]
entrypoint.sh脚本使用exec将java作为容器1号进程，避免无法接受linux 信号导致java进程无法正常退出。
#!/bin/bash
if [ -f /opt/cm/before.sh ]; then
source /opt/cm/before.sh;
fi
exec java $JAVA_OPTS org.springframework.boot.loader.JarLauncher
构建镜像
[root@localhost new]# docker build -t registry.xxx.com/layer/build:new .
Sending build context to Docker daemon 67.45MB
Step 1/14 : FROM registry.xxx.com/base/oracle-jdk:8u201 as builder
---> 1869b73a8999
Step 2/14 : WORKDIR /app
---> Using cache
---> 6973e49f31fa
Step 3/14 : COPY --chown=1001:1001 ./xxx-1.0.0.jar /app/lib/xxx-1.0.0.jar
---> Using cache
---> c5a17d5969ea
Step 4/14 : RUN java -Djarmode=layertools -jar /app/lib/xxx-1.0.0.jar extract
---> Using cache
---> 911074c3ef21
Step 5/14 : FROM registry.xxx.com/base/oracle-jdk:8u201
---> 1869b73a8999
Step 6/14 : ENV TZ=Asia/Shanghai
---> Using cache
---> 9304102c278e
Step 7/14 : ENV LC_ALL en_US.utf8
---> Using cache
---> 63fb6c823893
Step 8/14 : RUN mkdir -pv /app/logs && ln -s /app/logs /app/log && chown 1001:1001 -R /app
---> Running in 9cac9cb86507
mkdir: created directory ‘/app’
mkdir: created directory ‘/app/logs’
Removing intermediate container 9cac9cb86507
---> 858e77315e6b
Step 9/14 : WORKDIR /app
---> Running in 81c7173692fc
Removing intermediate container 81c7173692fc
---> 5c19ddda3114
Step 10/14 : COPY --chown=1001:1001 --from=builder /app/dependencies/ ./
---> 078e3f4a199c
Step 11/14 : COPY --chown=1001:1001 --from=builder /app/spring-boot-loader/ ./
---> 1542209ccc8b
Step 12/14 : COPY --chown=1001:1001 --from=builder /app/snapshot-dependencies/ ./
---> 75a9584e0952
Step 13/14 : COPY --chown=1001:1001 --from=builder /app/application/ ./
---> 555270edceea
Step 14/14 : ENTRYPOINT ["java", "org.springframework.boot.loader.JarLauncher"]
---> Running in fe99278683a2
Removing intermediate container fe99278683a2
---> 2cce0deab7e2
Successfully built 2cce0deab7e2
Successfully tagged registry.xxx.com/layer/build:new
查看分层详情，可以看到jar被拆分成4层分别由copy指令创建。
[root@localhost ~]# docker image history registry.xxx.com/layer/build:new
IMAGE CREATED CREATED BY SIZE COMMENT
2cce0deab7e2 28 hours ago /bin/sh -c #(nop) ENTRYPOINT ["java" "org.s… 0B
555270edceea 28 hours ago /bin/sh -c #(nop) COPY dir:2f5975d11563ae449… 248kB
75a9584e0952 28 hours ago /bin/sh -c #(nop) COPY dir:a3bb0870001a0ef25… 18.5kB
1542209ccc8b 28 hours ago /bin/sh -c #(nop) COPY dir:16d00ea1f180914e2… 252kB
078e3f4a199c 28 hours ago /bin/sh -c #(nop) COPY dir:1d3190ed598b634a5… 67.1MB
5c19ddda3114 28 hours ago /bin/sh -c #(nop) WORKDIR /app 0B
858e77315e6b 28 hours ago /bin/sh -c mkdir -pv /app/logs && ln -s /app… 9B
63fb6c823893 30 hours ago /bin/sh -c #(nop) ENV LC_ALL=en_US.utf8 0B
9304102c278e 30 hours ago /bin/sh -c #(nop) ENV TZ=Asia/Shanghai 0B
1869b73a8999 2 years ago /bin/sh -c set -ex; cd /tmp; curl -fsSLO… 302MB
<missing> 2 years ago /bin/sh -c #(nop) ENV JAVA_VERSION=8 JAVA_U… 0B
<missing> 2 years ago /bin/sh -c #(nop) ENV TZ=Asia/Shanghai LANG… 0B
<missing> 2 years ago /bin/sh -c set -ex; yum update -y; yum i… 116MB
<missing> 2 years ago /bin/sh -c #(nop) LABEL maintainer=currycan… 0B
<missing> 2 years ago /bin/sh -c #(nop) CMD ["/bin/bash"] 0B
<missing> 2 years ago /bin/sh -c #(nop) LABEL org.label-schema.sc… 0B
<missing> 2 years ago /bin/sh -c #(nop) ADD file:b3ebbe8bd304723d4… 204MB
对比发现jar包被拆分了。
[root@localhost new]# diff old.info new.info
1,16c1,18
< IMAGE CREATED CREATED BY SIZE COMMENT
< b9fc3a8a97f2 About an hour ago /bin/sh -c #(nop) ENTRYPOINT ["/bin/sh" "-c… 0B
< c823448f9582 About an hour ago /bin/sh -c #(nop) COPY --chown=1001:1001file… 128B
< 9a997f3962bf About an hour ago /bin/sh -c #(nop) COPY --chown=1001:1001file… 67.4MB
< f272c4e64f87 About an hour ago /bin/sh -c #(nop) WORKDIR /app 0B
< 1a526d3df7c2 About an hour ago /bin/sh -c mkdir -pv /app/{bin,lib,logs} && … 9B
< 63fb6c823893 2 hours ago /bin/sh -c #(nop) ENV LC_ALL=en_US.utf8 0B
< 9304102c278e 2 hours ago /bin/sh -c #(nop) ENV TZ=Asia/Shanghai 0B
< 1869b73a8999 2 years ago /bin/sh -c set -ex; cd /tmp; curl -fsSLO… 302MB
< <missing> 2 years ago /bin/sh -c #(nop) ENV JAVA_VERSION=8 JAVA_U… 0B
< <missing> 2 years ago /bin/sh -c #(nop) ENV TZ=Asia/Shanghai LANG… 0B
< <missing> 2 years ago /bin/sh -c set -ex; yum update -y; yum i… 116MB
< <missing> 2 years ago /bin/sh -c #(nop) LABEL maintainer=currycan… 0B
< <missing> 2 years ago /bin/sh -c #(nop) CMD ["/bin/bash"] 0B
< <missing> 2 years ago /bin/sh -c #(nop) LABEL org.label-schema.sc… 0B
< <missing> 2 years ago /bin/sh -c #(nop) ADD file:b3ebbe8bd304723d4… 204MB
---
> IMAGE CREATED CREATED BY SIZE COMMENT
> 2cce0deab7e2 8 minutes ago /bin/sh -c #(nop) ENTRYPOINT ["java" "org.s… 0B
> 555270edceea 8 minutes ago /bin/sh -c #(nop) COPY dir:2f5975d11563ae449… 248kB
> 75a9584e0952 8 minutes ago /bin/sh -c #(nop) COPY dir:a3bb0870001a0ef25… 18.5kB
> 1542209ccc8b 8 minutes ago /bin/sh -c #(nop) COPY dir:16d00ea1f180914e2… 252kB
> 078e3f4a199c 8 minutes ago /bin/sh -c #(nop) COPY dir:1d3190ed598b634a5… 67.1MB
> 5c19ddda3114 8 minutes ago /bin/sh -c #(nop) WORKDIR /app 0B
> 858e77315e6b 8 minutes ago /bin/sh -c mkdir -pv /app/logs && ln -s /app… 9B
> 63fb6c823893 2 hours ago /bin/sh -c #(nop) ENV LC_ALL=en_US.utf8 0B
> 9304102c278e 2 hours ago /bin/sh -c #(nop) ENV TZ=Asia/Shanghai 0B
> 1869b73a8999 2 years ago /bin/sh -c set -ex; cd /tmp; curl -fsSLO… 302MB
> <missing> 2 years ago /bin/sh -c #(nop) ENV JAVA_VERSION=8 JAVA_U… 0B
> <missing> 2 years ago /bin/sh -c #(nop) ENV TZ=Asia/Shanghai LANG… 0B
> <missing> 2 years ago /bin/sh -c set -ex; yum update -y; yum i… 116MB
> <missing> 2 years ago /bin/sh -c #(nop) LABEL maintainer=currycan… 0B
> <missing> 2 years ago /bin/sh -c #(nop) CMD ["/bin/bash"] 0B
> <missing> 2 years ago /bin/sh -c #(nop) LABEL org.label-schema.sc… 0B
> <missing> 2 years ago /bin/sh -c #(nop) ADD file:b3ebbe8bd304723d4… 204MB
推送到仓库
[root@localhost new]# docker push registry.xxx.com/layer/build:new
The push refers to repository [registry.xxx.com/layer/build]
e5409ea62302: Pushed
7167dfa406ea: Pushed
cf7e94a2dc11: Pushed
8e261e1bae2c: Pushed
770c31a84800: Pushed
c33745b35097: Layer already exists
2105884a1756: Layer already exists
174f56854903: Layer already exists
new: digest: sha256:faef10681394c01d1c2973ed10c7c33e7289eec25f22c90d085f6eef96ce3bff size: 2001
验证模拟开发推送代码更新镜像
开发摸了一天🐟终于开发出新版本
[root@localhost new]# md5sum bc-1.0.1.jar bc-1.0.0.jar
3792d3178a4e07708052b7effa9b12f8 xxx-1.0.1.jar
8ee570b94977668631355cb49c5d7cf1 xxx-1.0.0.jar
构建新版本，构建过程阶段二中使用了cache 仅更新了 application层
[root@localhost new]# docker image build -t registry.xxx.com/layer/build:new-1.0.1 .
Sending build context to Docker daemon 134.9MB
Step 1/16 : FROM registry.xxx.com/base/oracle-jdk:8u201 as builder
---> 1869b73a8999
Step 2/16 : WORKDIR /app
---> Using cache
---> 6973e49f31fa
Step 3/16 : COPY --chown=1001:1001 ./xxx-1.0.1.jar /app/lib/xxx-1.0.1.jar
---> b219210fd8ab
Step 4/16 : RUN java -Djarmode=layertools -jar /app/lib/xxx-1.0.1.jar extract
---> Running in d099c10b653c
Removing intermediate container d099c10b653c
---> 66a8593b0291
Step 5/16 : FROM registry.xxx.com/base/oracle-jdk:8u201
---> 1869b73a8999
Step 6/16 : ENV TZ=Asia/Shanghai
---> Using cache
---> 9304102c278e
Step 7/16 : ENV LC_ALL en_US.utf8
---> Using cache
---> 63fb6c823893
Step 8/16 : RUN mkdir -pv /app/logs && ln -s /app/logs /app/log && chown 1001:1001 -R /app
---> Using cache
---> 858e77315e6b
Step 9/16 : WORKDIR /app
---> Using cache
---> 5c19ddda3114
Step 10/16 : COPY --chown=1001:1001 ./entrypoint.sh /app/entrypoint.sh
---> Using cache
---> c47b74bb8cf9
Step 11/16 : COPY --chown=1001:1001 --from=builder /app/dependencies/ ./
---> Using cache
---> 078e3f4a199c
Step 12/16 : COPY --chown=1001:1001 --from=builder /app/spring-boot-loader/ ./
---> Using cache
---> 1542209ccc8b
Step 13/16 : COPY --chown=1001:1001 --from=builder /app/snapshot-dependencies/ ./
---> Using cache
---> 75a9584e0952
Step 14/16 : COPY --chown=1001:1001 --from=builder /app/application/ ./
---> 0f138b106caf
Step 15/16 : CMD ["exec"]
---> Using cache
---> a1170ae7a20e
Step 16/16 : ENTRYPOINT ["bash","/app/entrypoint.sh"]
---> Using cache
---> 5a6bb7613fc8
Successfully built 5a6bb7613fc8
Successfully tagged registry.xxx.com/layer/build:new-1.0.1
推送到仓库可以看到仅推送了application层 只有300K
docker push registry.xxx.com/layer/build:new-1.0.1
The push refers to repository [registry.xxx.com/layer/build]
c33a5c6456bd: Pushed
7167dfa406ea: Layer already exists
cf7e94a2dc11: Layer already exists
8e261e1bae2c: Layer already exists
770c31a84800: Layer already exists
c33745b35097: Layer already exists
2105884a1756: Layer already exists
174f56854903: Layer already exists
new-1.0.1: digest: sha256:53647bb45f0f0bb5bb8d56f14cd40deb22f0d5e4fce1200fed1c225a516dddb5 size: 2001
验证镜像
[root@localhost new]# docker run -it --rm -u 1001:1001 -e JAVA_OPTS="-XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintHeapAtGC -XX:+PrintTenuringDistribution -XX:+PrintGCApplicationStoppedTime -XX:+PrintGCApplicationConcurrentTime -XX:+PrintCommandLineFlags" registry.xxx.com/layer/build:new-1.0.1
可以看到打印出了堆栈信息（容器默认是不开启的）应用成功启动😋
[root@localhost ~]# docker run -it --rm -u 1001:1001 -e JAVA_OPTS="-XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintHeapAtGC -XX:+PrintTenuringDistribution -XX:+PrintGCApplicationStoppedTime -XX:+PrintGCApplicationConcurrentTime -XX:+PrintCommandLineFlags" registry.xxx.com/layer/build:new-1.0.1
-XX:InitialHeapSize=130478208 -XX:MaxHeapSize=2087651328 -XX:+PrintCommandLineFlags -XX:+PrintGCApplicationConcurrentTime -XX:+PrintGCApplicationStoppedTime -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+PrintHeapAtGC -XX:+PrintTenuringDistribution -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseParallelGC
{Heap before GC invocations=1 (full 0):
PSYoungGen total 37888K, used 32768K [0x00000000d6800000, 0x00000000d9200000, 0x0000000100000000)
eden space 32768K, 100% used [0x00000000d6800000,0x00000000d8800000,0x00000000d8800000)
from space 5120K, 0% used [0x00000000d8d00000,0x00000000d8d00000,0x00000000d9200000)
to space 5120K, 0% used [0x00000000d8800000,0x00000000d8800000,0x00000000d8d00000)
ParOldGen total 86016K, used 0K [0x0000000083800000, 0x0000000088c00000, 0x00000000d6800000)
eden space 32768K, 0% used [0x00000000d6800000,0x00000000d6800000,0x00000000d8800000)
from space 5120K, 72% used [0x00000000d8800000,0x00000000d8ba1748,0x00000000d8d00000)
to space 5120K, 0% used [0x00000000dad00000,0x00000000dad00000,0x00000000db200000)
ParOldGen total 86016K, used 8K [0x0000000083800000, 0x0000000088c00000, 0x00000000d6800000)
object space 86016K, 0% used [0x0000000083800000,0x0000000083802000,0x0000000088c00000)
Metaspace used 6799K, capacity 7074K, committed 7168K, reserved 1056768K
class space used 820K, capacity 935K, committed 1024K, reserved 1048576K
}
...
2023-08-17 20:50:42.253 INFO 1 --- [ main] org.springframework.boot.actuate.endpoint.web.EndpointLinksResolver.<init>(EndpointLinksResolver.java:58) - [] : Exposing 1 endpoint(s) beneath base path '/actuator'
2023-08-17 20:50:42.315 INFO 1 --- [ main] org.apache.juli.logging.DirectJDKLog.log(DirectJDKLog.java:173) - [] : Starting ProtocolHandler ["http-nio-8082"]
2023-08-17 20:50:42.349 INFO 1 --- [ main] org.springframework.boot.web.embedded.tomcat.TomcatWebServer.start(TomcatWebServer.java:220) - [] : Tomcat started on port(s): 8082 (http) with context path '/xxx'
2023-08-17 20:50:42.376 INFO 1 --- [ main] org.springframework.boot.StartupInfoLogger.logStarted(StartupInfoLogger.java:61) - [] : Started Application in 11.242 seconds (JVM running for 12.553)
对比两个版本可以发现只有application成hash值不一样 代码量增加了253kB-248kB=5KB
[root@localhost new]# docker image history registry.xxx.com/layer/build:new
IMAGE CREATED CREATED BY SIZE COMMENT
2cce0deab7e2 About an hour ago /bin/sh -c #(nop) ENTRYPOINT ["java" "org.s… 0B
555270edceea About an hour ago /bin/sh -c #(nop) COPY dir:2f5975d11563ae449… 248kB
75a9584e0952 About an hour ago /bin/sh -c #(nop) COPY dir:a3bb0870001a0ef25… 18.5kB
1542209ccc8b About an hour ago /bin/sh -c #(nop) COPY dir:16d00ea1f180914e2… 252kB
078e3f4a199c About an hour ago /bin/sh -c #(nop) COPY dir:1d3190ed598b634a5… 67.1MB
5c19ddda3114 About an hour ago /bin/sh -c #(nop) WORKDIR /app 0B
858e77315e6b About an hour ago /bin/sh -c mkdir -pv /app/logs && ln -s /app… 9B
63fb6c823893 3 hours ago /bin/sh -c #(nop) ENV LC_ALL=en_US.utf8 0B
9304102c278e 3 hours ago /bin/sh -c #(nop) ENV TZ=Asia/Shanghai 0B
1869b73a8999 2 years ago /bin/sh -c set -ex; cd /tmp; curl -fsSLO… 302MB
<missing> 2 years ago /bin/sh -c #(nop) ENV JAVA_VERSION=8 JAVA_U… 0B
<missing> 2 years ago /bin/sh -c #(nop) ENV TZ=Asia/Shanghai LANG… 0B
<missing> 2 years ago /bin/sh -c set -ex; yum update -y; yum i… 116MB
<missing> 2 years ago /bin/sh -c #(nop) LABEL maintainer=currycan… 0B
<missing> 2 years ago /bin/sh -c #(nop) CMD ["/bin/bash"] 0B
<missing> 2 years ago /bin/sh -c #(nop) LABEL org.label-schema.sc… 0B
<missing> 2 years ago /bin/sh -c #(nop) ADD file:b3ebbe8bd304723d4… 204MB
[root@localhost new]# docker image history registry.xxx.com/layer/build:new-1.0.1
IMAGE CREATED CREATED BY SIZE COMMENT
76aa6233354a 40 minutes ago /bin/sh -c #(nop) ENTRYPOINT ["java" "org.s… 0B
0f138b106caf 40 minutes ago /bin/sh -c #(nop) COPY dir:4d21cc5ce0d92794b… 253kB
75a9584e0952 About an hour ago /bin/sh -c #(nop) COPY dir:a3bb0870001a0ef25… 18.5kB
1542209ccc8b About an hour ago /bin/sh -c #(nop) COPY dir:16d00ea1f180914e2… 252kB
078e3f4a199c About an hour ago /bin/sh -c #(nop) COPY dir:1d3190ed598b634a5… 67.1MB
5c19ddda3114 About an hour ago /bin/sh -c #(nop) WORKDIR /app 0B
858e77315e6b About an hour ago /bin/sh -c mkdir -pv /app/logs && ln -s /app… 9B
63fb6c823893 3 hours ago /bin/sh -c #(nop) ENV LC_ALL=en_US.utf8 0B
9304102c278e 3 hours ago /bin/sh -c #(nop) ENV TZ=Asia/Shanghai 0B
1869b73a8999 2 years ago /bin/sh -c set -ex; cd /tmp; curl -fsSLO… 302MB
<missing> 2 years ago /bin/sh -c #(nop) ENV JAVA_VERSION=8 JAVA_U… 0B
<missing> 2 years ago /bin/sh -c #(nop) ENV TZ=Asia/Shanghai LANG… 0B
<missing> 2 years ago /bin/sh -c set -ex; yum update -y; yum i… 116MB
<missing> 2 years ago /bin/sh -c #(nop) LABEL maintainer=currycan… 0B
<missing> 2 years ago /bin/sh -c #(nop) CMD ["/bin/bash"] 0B
<missing> 2 years ago /bin/sh -c #(nop) LABEL org.label-schema.sc… 0B
<missing> 2 years ago /bin/sh -c #(nop) ADD file:b3ebbe8bd304723d4… 204MB
完
上述对开发没有恶意，大家都是辛苦勤劳上进的打工人。 哈哈哈又是摸🐟的一 天 ---Author Logn 引用：Spring Boot官方文档 Container Images