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dockerdockerfile

How to inspect docker image entrypoint?

If an base image has an entrypoint, will it be inherited by the image using it?

And, in case the image using it has not defined one, and running docker inspect shows the entrypoint is:

"Entrypoint": [
    "container-entrypoint"
]

What is this "container-entrypoint"? Didn't find docs on it, but it seems something generic.

Thanks.

Solution

  • If an base image has an entrypoint, will it be inherited by the image using it?

    Yes.

    What is this "container-entrypoint"? Didn't find docs on it, but it seems something generic.

    The ENTRYPOINT directive specifies the name of a command. In this case, that command happens to be container-entrypoint, which is presumably (a) contained in the image (b) in a directory that is on $PATH.

    The container-entrypoint command is probably a script. Assuming that your image has a shell, the easiest way to inspect it is to replace the entrypoint with a shell and then explore the container filesystem:

    docker run --entrypoint sh myimage

    Then examine directories in $PATH to find the script. There's a good chance it lives in /usr/local/bin.