entrypoint file not found

Another source of issues can be your shebang, if you have /bin/bash and you don't have bash in your image/base image it will tell your that your entrypoint is not found. This is one of the issues I ran into.

/usr/src/app may not be in your path so you should include the full path to the script. You also need to ensure that your entrypoint.sh is executable, docker will copy the permissions exactly as they are on your build host, so this step may not be needed depending on your scenario.

FROM ruby:2.4-alpine
WORKDIR /usr/src/app

COPY Gemfile /usr/src/app/Gemfile
COPY Gemfile.lock /usr/src/app/Gemfile.lock

RUN bundle config build.nokogiri --use-system-libraries
RUN bundle install --without development test

VOLUME /state

COPY . /usr/src/app/
RUN chmod 755 api-entrypoint.sh

ENTRYPOINT ["/usr/src/app/api-entrypoint.sh"]
CMD ["foreman", "start"]

I had this problem with Docker for Windows and the solution was changing the entrypoint script file from CRLF -> LF.

I had the same problem - the entrypoint was not found, but I was sure that it was there.

It seems that you can't use single quotes ' for the entrypoint/command.

So I changed from

ENTRYPOINT ['/foo/bar/script.sh']
CMD ['run']

to

ENTRYPOINT ["/foo/bar/script.sh"]
CMD ["run"]

and it works.