如何从头构建的容器'docker exec'？ [英] How to 'docker exec' a container built from scratch?

问题描述

我正在尝试 docker exec 一个从头开始构建的容器（例如，NATS容器）。似乎很简单，但是由于它是从头开始构建的，因此我无法访问 / bin / bash ， / bin / sh 以及几乎任何此类命令。

I am trying to docker exec a container that is built from scratch (say, a NATS container). Seems pretty straight-forward, but since it is built from scratch, I am unable to access /bin/bash, /bin/sh and literally any such command.

我收到错误： oci运行时错误（未找到命令） ，找不到文件等，具体取决于我输入的命令。）

I get the error: oci runtime error (command not found, file not found, etc. depending upon the command that I enter).

我尝试了一些命令，例如：

I tried some commands like:

docker exec -it <container name> /bin/bash
docker exec -it <container name> /bin/sh
docker exec -it <container name> ls

我的问题是，如何 docker exec 一个从头开始构建且仅包含二进制文件的容器？通过执行 docker exec ，我希望确定文件是否已成功从主机复制到容器（我有 COPY Dockerfile 中的code>）。

My question is, how do I docker exec a container that is built from scratch and consisting only of binaries? By doing a docker exec, I wish to find out if the files have been successfully copied from my host to the container (I have a COPY in the Dockerfile).

推荐答案

如果暂存容器正在运行，您可以将外壳程序（和其他所需的utils）复制到其文件系统中，然后执行它。该外壳将需要是静态二进制文件。 Busybox是一个不错的选择，因为它可以使其他二进制文件成倍增加。

If your scratch container is running you can copy a shell (and other needed utils) into its filesystem and then exec it. The shell would need to be a static binary. Busybox is a great choice here because it can double as so many other binaries.

完整示例：

# Assumes scratch container is last launched one, else replace with container ID of
# scratch image, e.g. from `docker ps`, for example:
# scratch_container_id=401b31621b36
scratch_container_id=$(docker ps -ql)

docker run -d busybox:latest sleep 100
busybox_container_id=$(docker ps -ql)
docker cp "$busybox_container_id":/bin/busybox .

# The busybox binary will become whatever you name it (or the first arg you pass to it), for more info run:
# docker run busybox:latest /bin/busybox
# The `busybox --install` command copies the binary with different names into a directory.

docker cp ./busybox "$scratch_container_id":/busybox

docker exec -it "$scratch_container_id" /busybox sh -c '
export PATH="/busybin:$PATH"
/busybox mkdir /busybin
/busybox --install /busybin
sh'

对于Kubernetes，我认为星历容器提供或将提供等效的功能。

For Kubernetes I think Ephemeral Containers provide or will provide equivalent functionality.

参考文献：
distroless java docker image error
https://github.com/GoogleContainerTools/distroless/issues/168#issuecomment-371077961

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