英文:
How to install java in container while writing it in Dockerfile?
问题
我在软件开发方面很幼稚。我想通过Dkron调度程序使用cron job运行一个jar文件。我在Docker中运行dkron（使用docker-compose up）。我正在传递"command": "java --version"，以查看是否可以从Dkron运行Java。由于Docker没有安装Java，我将dockerfile.hub文件更改为以下内容：
FROM alpine
LABEL maintainer="Victor Castell <victor@victorcastell.com>"
RUN set -x \
&& buildDeps='bash ca-certificates openssl tzdata' \
&& apk add --update $buildDeps \
&& apk add openjava8 #添加此行以安装Java
&& rm -rf /var/cache/apk/* \
&& mkdir -p /opt/local/dkron
ENV JAVA_HOME /usr/lib/jvm/java-1.8-openjdk #添加此行以安装Java
ENV PATH $PATH:$JAVA_HOME/bin #添加此行以安装Java
EXPOSE 8080 8946
ENV SHELL /bin/bash
WORKDIR /opt/local/dkron
COPY dkron .
COPY dkron-* ./
ENTRYPOINT ["/opt/local/dkron/dkron"]
CMD ["--help"]
当我再次运行docker-compose up时，没有任何错误，但是通过UI将"command": "java --version"传递后，dkron显示错误 - exec: "java": 在$PATH中找不到可执行文件。
我该如何解决这个问题？
提前谢谢。
英文:
I am naive in software development. I want to run a jar file from Dkron Scheduler using cron job. I am running dkron in docker(using docker-compose up). I am passing "command": "java --version" to see if I can run java from Dkron. As docker do not have java installed I changed the dockerfile.hub file to this:
FROM alpine
LABEL maintainer="Victor Castell <victor@victorcastell.com>"
RUN set -x \
&& buildDeps='bash ca-certificates openssl tzdata' \
&& apk add --update $buildDeps \
&& apk add openjava8 #add this line to install java
&& rm -rf /var/cache/apk/* \
&& mkdir -p /opt/local/dkron
ENV JAVA_HOME /usr/lib/jvm/java-1.8-openjdk #add this line to install java
ENV PATH $PATH:$JAVA_HOME/bin #add this line to install java
EXPOSE 8080 8946
ENV SHELL /bin/bash
WORKDIR /opt/local/dkron
COPY dkron .
COPY dkron-* ./
ENTRYPOINT ["/opt/local/dkron/dkron"]
CMD ["--help"]
When I again do docker-compose up it do not give any error, still on passing "command": "java --version" by json through UI, dkron shows error - exec : "java" : executable file not found in $PATH.
What can I do to resolve it?
Thanks in advance.
答案1
得分: 1
我能够使用 dkron 作为基础镜像，在 Docker 容器中创建了一个 JVM，并在其之上构建了另一个镜像。
以下是我为运行 Java 应用程序创建的 Dockerfile：
FROM dkron/dkron
WORKDIR /root/hello-world
COPY hello.java /root/hello-world
RUN apk add openjdk8
ENV JAVA_HOME /usr/lib/jvm/java-1.8-openjdk
ENV PATH $JAVA_HOME/bin:$PATH
RUN javac hello.java
然后我构建了镜像，假设其 ID 为 xxx。
接着我运行了该镜像，并构建了 dkron 服务器，命令如下：
docker run -p 8080:8080 xxx agent --server --bootstrap-expect=1 --node-name=node1
英文:
I was able to create JVM in docker container using dkron as the base image, (publically available) and build another image on top of it.
Here is dockerfile I created for running java application
FROM dkron/dkron
WORKDIR /root/hello-world
COPY hello.java /root/hello-world
RUN apk add openjdk8
ENV JAVA_HOME /usr/lib/jvm/java-1.8-openjdk
ENV PATH $JAVA_HOME/bin:$PATH
RUN javac hello.java
Then I build image. Let id be xxx
Then I ran the image and build dkron server as
docker run -p 8080:8080 xxx agent --server --bootstrap-expect=1 --node-name=node1
答案2
得分: 0
尝试使用以下文件：
FROM alpine
LABEL maintainer="Victor Castell <victor@victorcastell.com>"
RUN set -x \
&& buildDeps='bash ca-certificates openssl tzdata' \
&& apk add --update $buildDeps \
&& apk add openjdk8 \
&& rm -rf /var/cache/apk/* \
&& mkdir -p /opt/local/dkron
ENV JAVA_HOME=/usr/lib/jvm/java-1.8-openjdk
ENV PATH="$JAVA_HOME/bin:${PATH}"
EXPOSE 8080 8946
ENV SHELL /bin/bash
WORKDIR /opt/local/dkron
COPY dkron .
COPY dkron-* ./
ENTRYPOINT ["/opt/local/dkron/dkron"]
CMD ["--help"]
Alpine软件包中没有openjava8软件包。
编辑：更新环境变量。
英文:
Try this file
FROM alpine
LABEL maintainer="Victor Castell <victor@victorcastell.com>"
RUN set -x \
&& buildDeps='bash ca-certificates openssl tzdata' \
&& apk add --update $buildDeps \
&& apk add openjdk8 \
&& rm -rf /var/cache/apk/* \
&& mkdir -p /opt/local/dkron
ENV JAVA_HOME=/usr/lib/jvm/java-1.8-openjdk
ENV PATH="$JAVA_HOME/bin:${PATH}"
EXPOSE 8080 8946
ENV SHELL /bin/bash
WORKDIR /opt/local/dkron
COPY dkron .
COPY dkron-* ./
ENTRYPOINT ["/opt/local/dkron/dkron"]
CMD ["--help"]
alpine package doesn't have openjava8 packages.
Edit: Update ENV variables
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