rebuild docker image from specific step

Question

I have the below Dockerfile.

FROM ubuntu:14.04 MAINTAINER Samuel Alexander <[email protected]>  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"] 

While building image it failed in step 23 i.e.

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

Now when I rebuild it starts to build from step 23 as docker is using cache.

But if I want to rebuild the image from step 21 i.e.

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

How can I do that? Is deleting the cached image is the only option? Is there any additional parameter to do that?

Answer 1

You can rebuild the entire thing without using the cache by doing a

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

To force a rerun starting at a specific line, you can pass an arg that is otherwise unused. Docker passes ARG values as environment variables to your RUN command, so changing an ARG is a change to the command which breaks the cache. It's not even necessary to define it yourself on the RUN line.

FROM ubuntu:14.04 MAINTAINER Samuel Alexander <[email protected]>  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"] 

And then just run it with a unique arg:

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

To change the argument with every build, you can pass a timestamp as the arg:

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

or:

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

---

As an aside, I'd recommend the following changes to keep your layers smaller, the more you can merge the cleanup and delete steps on a single RUN command after the download and install, the smaller your final image will be. Otherwise your layers will include all the intermediate steps between the download and cleanup:

FROM ubuntu:14.04 MAINTAINER Samuel Alexander <[email protected]>  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"] 

Answer 2

One workaround:

1. Locate the step you want to execute from.
2. Before that step put a simple dummy operation like "RUN pwd"

Then just build your Dockerfile. It will take everything up to that step from the cache and then execute the lines after the dummy command.