dockerdocker-entrypointdocker-cmd

Unable to quit docker run with CTRL+C using exec format of ENTRYPOINT and CMD

In my Dockerfile, I was previously using the following CMD so that the Apache server would launch and since it was running in the foreground, the container would remain running and I could kill it using CTRL + C without issue.

CMD ["/usr/sbin/apachectl", "-D", "FOREGROUND", "-k", "start"]

I've since needed to update my Dockerfile so that I can run another script before Apache starts so I added an entrypoint script and modified my Dockerfile...

Dockerfile:

...

EXPOSE 80 

# Default process to run on container startup
ENTRYPOINT ["/entrypoint.d/docker-entrypoint.sh"]

# Default command to run container
CMD ["/usr/sbin/apachectl", "-D", "FOREGROUND", "-k", "start"]

docker-entrypoint.sh:

#!/usr/bin/env bash

# Inject Environment Variables
source ${ENTRYPOINT_FOLDER}/env.sh

# Run the main container process (from the Dockerfile CMD)
exec "$@"

In both of these updated commands I'm using the exec form of ENTRYPOINT and CMD, the arguments set in CMD are to launch Apache in the foreground using the line exec "$@" in the entrypoint script, but doing this doesn't allow me to use CTRL + C any longer to quit from the terminal window.

What am I doing wrong here?

Solution

  • While I had used the proper exec forms for both ENTRYPOINT and CMD, the quit signal still wasn't working.

    The resolution for this issue was to add the options -t and -i in my docker run invocation.

    Before:

    docker run --env-file=<env-file-path> --rm -p 8080:80 ...

    After:

    docker run --env-file=<env-file-path> -t -i --rm -p 8080:80 ...

    Reference: https://github.com/moby/moby/issues/2838#issuecomment-29205965

    I also wanted to give a thank you to CharlesDuffy for helping me with this issue, I learned some things from you regarding debugging bash scripts. đź‘Ť