bashdockercontainersshdocker-entrypoint

Εxecute commands with args and override entrypoint on docker run

I am trying to override the entrypoint in a docker image with a script execution that accepts arguments, and it fails as follows

▶ docker run --entrypoint "/bin/sh -c 'my-script.sh arg1 arg2'" my-image:latest
docker: Error response from daemon: OCI runtime create failed: container_linux.go:380: starting container process caused: exec: "/bin/sh -c 'myscript.sh arg1 arg2'": stat /bin/sh -c 'my-script.sh arg1 arg2': no such file or directory: unknown.

However when I exec to the container, the above command succeeds:

▶  docker run --entrypoint sh -it my-image:latest
~ $ /bin/sh -c 'my-script.sh arg1 arg2'
Success

Am I missing sth in the syntax?

Solution

  • Remember that arguments after the container image name are simply passed to the ENTRYPOINT script. So you can write:

    docker run --entrypoint my-script.sh my-image:latest arg1 arg2

    For example, if I have my-script.sh (mode 0755) containing:

    #!/bin/sh

for arg in "$@"; do
    echo "Arg: $arg"
done

    And a Dockerfile like this:

    FROM docker.io/alpine:latest

COPY my-script.sh /usr/local/bin/
ENTRYPOINT ["date"]

    Then I can run:

    docker run --rm --entrypoint my-script.sh my-image arg1 arg2

    And get as output:

    Arg: arg1
Arg: arg2

    If you want to run an arbitrary sequence of shell commands, you can of course do this:

    docker run --rm --entrypoint sh my-image \
  -c 'ls -al && my-script.sh arg1 arg2'