保存 Dockerfile ENV 变量以供将来使用

Question

我想将 Dockerfile 中设置的 PATH 和 LD_LIBRARY_PATH 保存到 .bashrc 以供将来使用。 但是，看起来PATH 已正确保存，但LD_LIBRARY_PATH 未正确保存 例如，以下简单的 Dockerfile 将这些变量保存到临时文件中：

FROM nvidia/cuda:9.0-devel-centos7 AS devel
ENV PATH=/opt/pgi/linux86-64/18.4/bin:$PATH
ENV LD_LIBRARY_PATH=/opt/pgi/linux86-64/18.4/lib:$LD_LIBRARY_PATH
RUN touch mylibpath && \
    touch mybinpath && \
    echo $PATH >> mybinpath && \
    echo $LD_LIBRARY_PATH >> mylibpath

结果是PATH 具有正确的值，而LD_LIBRARY_PATH 为空白，如下所示。 但是，如果我将 LD_LIBRARY_PATH 重命名为 ALD_LIBRARY_PATH 之类的名称，它会打印出正确的值。 我错过了什么？

================Before renaming =======================

$ sudo docker build --no-cache -t dshawul/acecast:latest .
Sending build context to Docker daemon  2.048kB
Step 1/4 : FROM nvidia/cuda:9.0-devel-centos7 AS devel
 ---> 96c10ed77499
Step 2/4 : ENV PATH /opt/pgi/linux86-64/18.4/bin:$PATH
 ---> Running in 2e3cf9a3ad64
 ---> cd56324327ab
Removing intermediate container 2e3cf9a3ad64
Step 3/4 : ENV LD_LIBRARY_PATH /opt/pgi/linux86-64/18.4/lib:$LD_LIBRARY_PATH
 ---> Running in d228c9421efc
 ---> 43c2d0043ff5
Removing intermediate container d228c9421efc
Step 4/4 : RUN touch mylibpath &&     touch mybinpath &&     echo $PATH >> mybinpath &&     echo $LD_LIBRARY_PATH >> mylibpath
 ---> Running in 52ba4a205815
 ---> e9aede6ab347
Removing intermediate container 52ba4a205815
Successfully built e9aede6ab347
Successfully tagged dshawul/acecast:latest

$ sudo docker run -it dshawul/acecast:latest
[root@efdfdcf693d9 /]# cat mybinpath
/opt/pgi/linux86-64/18.4/bin:/usr/local/nvidia/bin:/usr/local/cuda/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
[root@efdfdcf693d9 /]# cat mylibpath

[root@efdfdcf693d9 /]# exit
exit

==================After renaming ==============================

$ sudo docker build --no-cache -t dshawul/acecast:latest .
Sending build context to Docker daemon  2.048kB
Step 1/4 : FROM nvidia/cuda:9.0-devel-centos7 AS devel
 ---> 96c10ed77499
Step 2/4 : ENV PATH /opt/pgi/linux86-64/18.4/bin:$PATH
 ---> Running in 3628b77881b4
 ---> c98fc82bba60
Removing intermediate container 3628b77881b4
Step 3/4 : ENV ALD_LIBRARY_PATH /opt/pgi/linux86-64/18.4/lib:$ALD_LIBRARY_PATH
 ---> Running in 5eea6a5675c0
 ---> 7da3fb187682
Removing intermediate container 5eea6a5675c0
Step 4/4 : RUN touch mylibpath &&     touch mybinpath &&     echo $PATH >> mybinpath &&     echo $ALD_LIBRARY_PATH >> mylibpath
 ---> Running in ebdfdd5e3762
 ---> c175b1fbd2c1
Removing intermediate container ebdfdd5e3762
Successfully built c175b1fbd2c1
Successfully tagged dshawul/acecast:latest

$ sudo docker run -it dshawul/acecast:latest
[root@9cd1ed4fdf3a /]# cat mybinpath
/opt/pgi/linux86-64/18.4/bin:/usr/local/nvidia/bin:/usr/local/cuda/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
[root@9cd1ed4fdf3a /]# cat mylibpath
/opt/pgi/linux86-64/18.4/lib:
[root@9cd1ed4fdf3a /]# exit
exit

==========================================================

Answer 1

在您的Dockerfile 中，如果您只是将软件安装到/usr/bin 和/usr/lib 之类的目录中，这些目录已经在$PATH 和/etc/ld.so.conf 中，那么这是最简单的。由于您描述的是在隔离文件系统中运行的东西上的可重现构建过程，因此您并没有真正“污染已安装的操作系统”。

我已经看到 some hints that Docker 可能会默默地剥离、忽略或重置 LD_LIBRARY_PATH 环境变量，尽管我找不到明确的文档说明。

Answer 2

您的环境中发生了其他事情，可能是缓存的图像，因为我无法重现您的问题：

$ cat df.so-51670836
FROM nvidia/cuda:9.0-devel-centos7 AS devel
ENV PATH=/opt/pgi/linux86-64/18.4/bin:$PATH
ENV LD_LIBRARY_PATH=/opt/pgi/linux86-64/18.4/lib:$LD_LIBRARY_PATH
RUN touch mylibpath && \
    touch mybinpath && \
    echo $PATH >> mybinpath && \
    echo $LD_LIBRARY_PATH >> mylibpath

$ docker build -t so-51670836 -f df.so-51670836 .
Sending build context to Docker daemon  23.04kB
Step 1/4 : FROM nvidia/cuda:9.0-devel-centos7 AS devel
 ---> 96c10ed77499
Step 2/4 : ENV PATH=/opt/pgi/linux86-64/18.4/bin:$PATH
 ---> Running in c152383485fd
Removing intermediate container c152383485fd
 ---> c47e029b5e50
Step 3/4 : ENV LD_LIBRARY_PATH=/opt/pgi/linux86-64/18.4/lib:$LD_LIBRARY_PATH
 ---> Running in b58a94b16980
Removing intermediate container b58a94b16980
 ---> 3c02bc748518
Step 4/4 : RUN touch mylibpath &&     touch mybinpath &&     echo $PATH >> mybinpath &&     echo $LD_LIBRARY_PATH >> mylibpath
 ---> Running in e81f4e821d28
Removing intermediate container e81f4e821d28
 ---> f5c5c2868350
Successfully built f5c5c2868350
Successfully tagged so-51670836:latest

$ docker run -it --rm so-51670836
[root@dfcb06ce3ac1 /]# cat my
mybinpath  mylibpath
[root@dfcb06ce3ac1 /]# cat mylibpath
/opt/pgi/linux86-64/18.4/lib:/usr/local/nvidia/lib:/usr/local/nvidia/lib64
[root@dfcb06ce3ac1 /]# cat mybinpath
/opt/pgi/linux86-64/18.4/bin:/usr/local/nvidia/bin:/usr/local/cuda/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
[root@dfcb06ce3ac1 /]# exit
exit

$ docker version
Client:
 Version:           18.06.0-ce
 API version:       1.38
 Go version:        go1.10.3
 Git commit:        0ffa825
 Built:             Wed Jul 18 19:09:33 2018
 OS/Arch:           linux/amd64
 Experimental:      true

Server:
 Engine:
  Version:          18.06.0-ce
  API version:      1.38 (minimum version 1.12)
  Go version:       go1.10.3
  Git commit:       0ffa825
  Built:            Wed Jul 18 19:07:38 2018
  OS/Arch:          linux/amd64
  Experimental:     true