bash - 在 $PATH Dockerfile 中找不到可执行文件

Question

我正在为应用程序构建 Dockerfile。我想在容器开始运行时执行带参数的 bash 脚本，所以我将其作为入口点。但是，Docker 找不到我的脚本所在的目录。该脚本位于 Intellij Idea 项目文件夹中，路径实际上如下所示:/home/user/Documents/folder1/folder2/folder3/Projectname/runapp.sh

我尝试将此目录挂载为卷，但在运行构建镜像时发生错误:

docker: Error response from daemon: OCI runtime create failed: container_linux.go:348: starting container process caused "exec: \"runapp.sh\": executable file not found in $PATH": unknown.

这种行为的原因可能是什么？我还能如何从 Dockerfile 访问此 bash 脚本？

这是 Dockerfile 的样子:

FROM java:8

ENV SCALA_VERSION 2.11.8
ENV SBT_VERSION 1.1.1
ENV SPARK_VERSION 2.2.0
ENV SPARK_DIST spark-$SPARK_VERSION-bin-hadoop2.6
ENV SPARK_ARCH $SPARK_DIST.tgz
ENV NEO4J_CONFIG default
ENV BENCHMARK_NAME default

WORKDIR /opt

# Install Scala
RUN \
  cd /root && \
  curl -o scala-$SCALA_VERSION.tgz http://downloads.typesafe.com/scala/$SCALA_VERSION/scala-$SCALA_VERSION.tgz && \
  tar -xf scala-$SCALA_VERSION.tgz && \
  rm scala-$SCALA_VERSION.tgz && \
  echo >> /root/.bashrc && \
  echo 'export PATH=~/scala-$SCALA_VERSION/bin:$PATH' >> /root/.bashrc

# Install SBT
RUN \
  curl -L -o sbt-$SBT_VERSION.deb https://dl.bintray.com/sbt/debian/sbt-$SBT_VERSION.deb && \
  dpkg -i sbt-$SBT_VERSION.deb && \
  rm sbt-$SBT_VERSION.deb

# Install Spark
RUN \
    cd /opt && \
    curl -o $SPARK_ARCH http://d3kbcqa49mib13.cloudfront.net/$SPARK_ARCH && \
    tar xvfz $SPARK_ARCH && \
    rm $SPARK_ARCH && \
    echo 'export PATH=$SPARK_DIST/bin:$PATH' >> /root/.bashrc

EXPOSE 9851 9852 4040 7474 7687 7473

VOLUME /home/user/Documents/folder1/folder2/folder3/Projectname /workdir1

WORKDIR /workdir1

ENTRYPOINT ["runapp.sh"]

CMD ["$NEO4J_CONFIG", "$BENCHMARK_NAME"]

Answer 1

我认为您误解了 Docker 中的卷。 (参见 What is the purpose of VOLUME in Dockerfile)

我在引用 @VonC answer :

A volume is a persistent data stored in /var/lib/docker/volumes/...

• You can either declare it in a Dockerfile, which means each time a container is stated from the image, the volume is created (empty), even if you don't have any -v option.

• You can declare it on runtime docker run -v [host-dir:]container-dir. combining the two (VOLUME + docker run -v) means that you can mount the content of a host folder into your volume persisted by the container in /var/lib/docker/volumes/....

• docker volume create creates a volume without having to define a Dockerfile and build an image and run a container. It is used to quickly allow other containers to mount said volume.

所以你应该在启动容器时使用docker run -v/home/user/Documents/folder1/folder2/folder3/Projectname:/workdir1

你的 Dockerfile 卷声明应该是:

VOLUME/workdir1

也就是说，您同时定义了 Entrypoint 和 CMD。 CMD 是做什么用的？如果不使用 runapp.sh，您将永远不会使用您的图像？我更喜欢仅使用 CMD 进行开发，因为您仍然可以使用此语法执行 docker run -it my_container bash 以进行调试。

这次我使用来自What is the difference between CMD and ENTRYPOINT in a Dockerfile? 的@Daishi 回答

The ENTRYPOINT specifies a command that will always be executed when the container starts.

The CMD specifies arguments that will be fed to the ENTRYPOINT.

If you want to make an image dedicated to a specific command you will use ENTRYPOINT ["/path/dedicated_command"]

Otherwise, if you want to make an image for general purpose, you can leave ENTRYPOINT unspecified and use CMD ["/path/dedicated_command"] as you will be able to override the setting by supplying arguments to docker run

此外，runapp.sh 不在您的$PATH 中，并且您在没有绝对路径的情况下调用它，因此即使挂载了卷也找不到该文件正确。你可以只使用:

CMD/workdir1/runapp.sh "$NEO4J_CONFIG""$BENCHMARK_NAME"

现在请注意，在您的主机上您提到 shell 脚本名为 script.sh 并且您在 Dockerfile 中调用了 runapp.sh，我希望这是一个错字.顺便说一句，您的脚本需要可执行。