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Dockerfile

FROM centos:7 COPY docker-entrypoint.sh /data/ ENTRYPOINT ["/data/docker-entrypoint.sh"]

docker-entrypoint.sh

exec /usr/sbin/init && systemctl restart autofs %% python /data/myapp.py

I need to run /usr/sbin/init as the first command then run subsequent commands such as systemctl restart autofs and python myapp.py

I cant seem to get all working inside docker-entrypoint.sh because /usr/sbin/init does not return

if i change docker-entrypoint.sh to

/usr/sbin/init & systemctl restart autofs && python /data/myapp.py

it fails with error in d-bus

what can i do so the container runs /usr/sbin/init, systemctl restart autofs and python /data/myapp.py in that order when "docker run" is executed?

Is there any other ways to run commands after /usr/sbin/init is executed? i've tried putting systemctl as CMD in Dockerfile

FROM centos:7 ENTRYPOINT ["/usr/sbin/init"] CMD ["systemctl restart autofs"]

but CMD is never executed

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    The error about d-bus comes from systemctl to have executed. That's because systemctl uses d-bus to talk to the systemd daemon. May be you want to avoid the init/dbus thing with the docker-systemctl-replacement :D Commented Mar 15, 2018 at 23:24

1 Answer 1

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23

Declaring

ENTRYPOINT ["/usr/sbin/init"] CMD ["systemctl"]

Will result in:

/usr/sbin/init systemctl

In other words, the ENTRYPOINT directive sets the executable which is used to execute the command given from the COMMAND directive.

The default ENTRYPOINT is /bin/sh -c so /bin/sh -c /data/docker-entrypoint.sh should work, if /data/docker-entrypoint.sh contains:

/usr/sbin/init systemctl restart autofs python /data/myapp.py

That means: You don't have to change the ENTRYPOINT

If you change the the ENTRYPOINT to /data/docker-entrypoint.sh than it should contain something like:

/usr/sbin/init systemctl restart autofs python /data/myapp.py # run the command given as arguments from CMD exec "$@"

reference

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2 Comments

this cannot work. your shell script will have PID 1 and you need init to be PID 1.
Indeed I've got an error message: "System has not been booted with systemd as init system (PID 1). Can't operate."

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