码头图像中的重复层

Question

在创建了对接图像之后，我看到了重复的图层和比预期更大的图像大小。出什么问题了？

Dockerfile

FROM ubuntu:latest
RUN apt-get -y update && apt-get -y upgrade
RUN apt-get -y install wget
RUN wget https://downloads.apache.org/tomcat/tomcat-8/v8.5.61/bin/apache-tomcat-8.5.61.tar.gz -O /tmp/tomcat.tar.gz
RUN useradd -rm -d /home/ubuntu -s /bin/bash -g root -G sudo -u 1001 ubuntu
COPY data /usr/local/data
RUN cd /tmp && tar xvfz tomcat.tar.gz
RUN mkdir /usr/local/tomcat
RUN cp -Rv /tmp/apache-tomcat-8.5.61/* /usr/local/tomcat/ 
RUN chown -R ubuntu:root /usr/local/tomcat
USER ubuntu
EXPOSE 8080    
CMD /usr/local/tomcat/bin/catalina.sh run

层

jenkins@test-VirtualBox:~/docker/ubuntu$ docker history myimage
IMAGE               CREATED             CREATED BY                                      SIZE                COMMENT
357a69f163e2        21 seconds ago      /bin/sh -c chown -R ubuntu:root /usr/local/d…   845MB               
3ad0b14611cf        30 seconds ago      /bin/sh -c chown -R ubuntu:root /usr/local/t…   14.6MB              
efcd2635eb2a        33 seconds ago      /bin/sh -c #(nop) COPY dir:175f4c922c826712a…   845MB               
1cd81d0f50c7        42 seconds ago      /bin/sh -c cp -Rv /tmp/apache-tomcat-8.5.61/…   14.6MB              
e3f848fe5958        2 minutes ago       /bin/sh -c cd /tmp && tar xvfz tomcat.tar.gz    14.6MB              
<missing>           2 weeks ago         /bin/sh -c #(nop) ADD file:4f15c4475fbafb3fe…   72.9MB 

Answer 1

通过在chown命令中使用COPY命令并在RUN命令中组合命令来解决此问题。这是因为Dockerfile中的每个RUN命令都会生成一个新的中间映像，即" layer "，它由文件系统上从上一层更改的任何内容组成。

Dockerfile

FROM ubuntu:latest
RUN apt-get -y update && apt-get -y upgrade
RUN apt-get -y install wget
RUN wget https://downloads.apache.org/tomcat/tomcat-8/v8.5.61/bin/apache-tomcat-8.5.61.tar.gz -O /tmp/tomcat.tar.gz
RUN useradd -rm -d /home/ubuntu -s /bin/bash -g root -G sudo -u 1001 ubuntu
COPY --chown=ubuntu:root data /usr/local/data
RUN cd /tmp && tar xvfz tomcat.tar.gz && \
    mkdir /usr/local/tomcat && \
    cp -Rv /tmp/apache-tomcat-8.5.61/* /usr/local/tomcat/ && \
    chown -R ubuntu:root /usr/local/tomcat
USER ubuntu
EXPOSE 8080    
CMD /usr/local/tomcat/bin/catalina.sh run

层

jenkins@test-VirtualBox:~/docker/ubuntu$ docker history myimage:fix
IMAGE               CREATED              CREATED BY                                      SIZE                COMMENT
ddb45a77bcb6        21 seconds ago       /bin/sh -c cd /tmp && tar xvfz tomcat.tar.gz…   29.2MB              
5610752cb747        23 seconds ago       /bin/sh -c #(nop) COPY --chown=ubuntu:rootdi…   845MB               
<missing>           2 weeks ago          /bin/sh -c #(nop) ADD file:4f15c4475fbafb3fe…   72.9MB