从特定步骤重建Docker映像

Question

我有下面的Dockerfile。

FROM ubuntu:14.04
MAINTAINER Samuel Alexander <[e-mail]>

RUN apt-get -y install software-properties-common
RUN apt-get -y update

# Install Java.
RUN echo oracle-java8-installer shared/accepted-oracle-license-v1-1 select true | debconf-set-selections
RUN add-apt-repository -y ppa:webupd8team/java
RUN apt-get -y update
RUN apt-get install -y oracle-java8-installer
RUN rm -rf /var/lib/apt/lists/*
RUN rm -rf /var/cache/oracle-jdk8-installer

# Define working directory.
WORKDIR /work

# Define commonly used JAVA_HOME variable
ENV JAVA_HOME /usr/lib/jvm/java-8-oracle

# JAVA PATH
ENV PATH /usr/lib/jvm/java-8-oracle/bin:$PATH

# Install maven
RUN apt-get -y update
RUN apt-get -y install maven

# Install Open SSH and git
RUN apt-get -y install openssh-server
RUN apt-get -y install git

# clone Spark
RUN git clone https://github.com/apache/spark.git
WORKDIR /work/spark
RUN mvn -DskipTests clean package

# clone and build zeppelin fork
RUN git clone https://github.com/apache/incubator-zeppelin.git
WORKDIR /work/incubator-zeppelin
RUN mvn clean package -Pspark-1.6 -Phadoop-2.6 -DskipTests

# Install Supervisord
RUN apt-get -y install supervisor
RUN mkdir -p var/log/supervisor

# Configure Supervisord
COPY conf/supervisord.conf /etc/supervisor/conf.d/supervisord.conf

# bash
RUN sed -i s#/home/git:/bin/false#/home/git:/bin/bash# /etc/passwd

EXPOSE 8080 8082
CMD ["/usr/bin/supervisord"]

构建图像时，它在步骤23中失败，即

RUN mvn clean package -Pspark-1.6 -Phadoop-2.6 -DskipTests

现在，当我重建时，由于docker使用缓存，它从步骤23开始构建。

但是，如果我想从步骤21重建图像，即

RUN git clone https://github.com/apache/incubator-zeppelin.git

我怎样才能做到这一点？删除缓存的图像是唯一的选择吗？是否有其他参数可以做到这一点？

Answer 1

您可以通过执行以下操作来重建整个内容，而无需使用缓存

docker build --no-cache -t user/image-name

要强制从特定行开始重新运行，可以传递一个未使用的arg。Docker将ARG值作为环境变量传递给RUN命令，因此更改ARG就是对命令的更改，这会中断缓存。甚至不必在RUN行上自己定义它。

FROM ubuntu:14.04
MAINTAINER Samuel Alexander <[e-mail]>

RUN apt-get -y install software-properties-common
RUN apt-get -y update

# Install Java.
RUN echo oracle-java8-installer shared/accepted-oracle-license-v1-1 select true | debconf-set-selections
RUN add-apt-repository -y ppa:webupd8team/java
RUN apt-get -y update
RUN apt-get install -y oracle-java8-installer
RUN rm -rf /var/lib/apt/lists/*
RUN rm -rf /var/cache/oracle-jdk8-installer

# Define working directory.
WORKDIR /work

# Define commonly used JAVA_HOME variable
ENV JAVA_HOME /usr/lib/jvm/java-8-oracle

# JAVA PATH
ENV PATH /usr/lib/jvm/java-8-oracle/bin:$PATH

# Install maven
RUN apt-get -y update
RUN apt-get -y install maven

# Install Open SSH and git
RUN apt-get -y install openssh-server
RUN apt-get -y install git

# clone Spark
RUN git clone https://github.com/apache/spark.git
WORKDIR /work/spark
RUN mvn -DskipTests clean package

# clone and build zeppelin fork, changing INCUBATOR_VER will break the cache here
ARG INCUBATOR_VER=unknown
RUN git clone https://github.com/apache/incubator-zeppelin.git
WORKDIR /work/incubator-zeppelin
RUN mvn clean package -Pspark-1.6 -Phadoop-2.6 -DskipTests

# Install Supervisord
RUN apt-get -y install supervisor
RUN mkdir -p var/log/supervisor

# Configure Supervisord
COPY conf/supervisord.conf /etc/supervisor/conf.d/supervisord.conf

# bash
RUN sed -i s#/home/git:/bin/false#/home/git:/bin/bash# /etc/passwd

EXPOSE 8080 8082
CMD ["/usr/bin/supervisord"]

然后使用唯一的arg运行它：

docker build --build-arg INCUBATOR_VER=20160613.2 -t user/image-name .

要在每次构建时更改参数，您可以将时间戳作为arg传递：

docker build --build-arg INCUBATOR_VER=$(date +%Y%m%d-%H%M%S) -t user/image-name .

要么：

docker build --build-arg INCUBATOR_VER=$(date +%s) -t user/image-name .

顺便说一句，我建议进行以下更改以使您的图层更小，RUN在下载并安装后，您可以在单个命令上合并清理和删除步骤的内容越多，最终映像就越小。否则，您的图层将包括下载和清理之间的所有中间步骤：

FROM ubuntu:14.04
MAINTAINER Samuel Alexander <[e-mail]>

RUN DEBIAN_FRONTEND=noninteractive \
    apt-get -y install software-properties-common && \
    apt-get -y update

# Install Java.
RUN echo oracle-java8-installer shared/accepted-oracle-license-v1-1 select true | debconf-set-selections && \
    add-apt-repository -y ppa:webupd8team/java && \
    apt-get -y update && \
    DEBIAN_FRONTEND=noninteractive \
    apt-get install -y oracle-java8-installer && \
    apt-get clean && \
    rm -rf /var/lib/apt/lists/* && \
    rm -rf /var/cache/oracle-jdk8-installer && \

# Define working directory.
WORKDIR /work

# Define commonly used JAVA_HOME variable
ENV JAVA_HOME /usr/lib/jvm/java-8-oracle

# JAVA PATH
ENV PATH /usr/lib/jvm/java-8-oracle/bin:$PATH

# Install maven
RUN apt-get -y update && \
    DEBIAN_FRONTEND=noninteractive \
    apt-get -y install 
      maven \
      openssh-server \
      git \
      supervisor && \
    apt-get clean && \
    rm -rf /var/lib/apt/lists/*

# clone Spark
RUN git clone https://github.com/apache/spark.git
WORKDIR /work/spark
RUN mvn -DskipTests clean package

# clone and build zeppelin fork
ARG INCUBATOR_VER=unknown
RUN git clone https://github.com/apache/incubator-zeppelin.git
WORKDIR /work/incubator-zeppelin
RUN mvn clean package -Pspark-1.6 -Phadoop-2.6 -DskipTests

# Configure Supervisord
RUN mkdir -p var/log/supervisor
COPY conf/supervisord.conf /etc/supervisor/conf.d/supervisord.conf

# bash
RUN sed -i s#/home/git:/bin/false#/home/git:/bin/bash# /etc/passwd

EXPOSE 8080 8082
CMD ["/usr/bin/supervisord"]