DockerFile运行java程序

Question

嗨,我是Docker的新手,并尝试从头开始编写新图像.我正在编写这个dockerFile来编译和运行同一目录中可用的简单java程序.

这是dockerfile.

FROM scratch
CMD javac HelloWorld.java
CMD java HelloWorld

Docker构建成功,如下所示

[root@hadoop01 myjavadir]# docker build -t runhelloworld .
Sending build context to Docker daemon 3.072 kB
Sending build context to Docker daemon
Step 0 : FROM scratch
 --->
Step 1 : CMD javac HelloWorld.java
 ---> Running in 7298ad7e902f
 ---> f5278ae25f0c
Removing intermediate container 7298ad7e902f
Step 2 : CMD java HelloWorld
 ---> Running in 0fa2151dc7b0
 ---> 25453e89b3f0
Removing intermediate container 0fa2151dc7b0
Successfully built 25453e89b3f0

但是当我尝试运行时,它会抛出以下错误:

[root@hadoop01 myjavadir]# docker run runhelloworld
exec: "/bin/sh": stat /bin/sh: no such file or directory
Error response from daemon: Cannot start container 676717677d3f1bf3b0b000d68b60c32826939b8c6ec1b5f2e9876969c60e22a4: [8] System error: exec: "/bin/sh": stat /bin/sh: no such file or directory
[root@hadoop01 myjavadir]#  exec: "/bin/sh": stat /bin/sh: no such file or directory
bash: exec:: command not found

请帮忙解决同样的问题.

---

chaning第二行后更新RUN.

[root@hadoop01 myjavadir]# docker build -t runhelloworld . 
Sending build context to Docker daemon 3.584 kB 
Sending build context to Docker daemon 
Step 0 : FROM scratch 
---> 
Step 1 : RUN javac HelloWorld.java 
---> Running in fdef2d65ac58 
exec: "/bin/sh": stat /bin/sh: no such file or directory [8] 
System error: exec: "/bin/sh": stat /bin/sh: no such file or directory

Answer 1

说明

从Dockerfile引用.

Dockerfile中只能有一条CMD指令.如果列出多个CMD,则只有最后一个CMD才会生效.

这就是为什么javac没有执行命令并找到启动容器结果的no such file or directory原因.

CMD并ENTRYPOINT用于执行容器(入口点级别)后应启动的任务.

CMD的主要目的是为执行容器提供默认值.

这适用于该行CMD java HelloWorld,但不适用于CMD javac HelloWorld.java构建步骤.这RUN是为了什么.

解

将第二行更改为RUN javac HelloWorld.java.

FROM scratch
RUN javac HelloWorld.java
CMD java HelloWorld

生成的提交图像[来自第二行]将用于Dockerfile中的下一步.

更新

正如Diyoda指出的那样,确保FROM图像提供java.