Friday, July 12, 2019

dockerfile cmd and entrypoint

very confusing, poor design IMHO


FROM ubuntu
ENV myname "pierre"
ENTRYPOINT ["/bin/bash", "-c", "echo hello ${myname}"]

docker built -t hello01 .
docker run hello01

FROM ubuntu
ENTRYPOINT ["sleep"]

docker built -t hello02 .
docker run hello02

#this sleep for 5s
docker run hello02 5

#this gives error because parameter is missing
docker run hello02

FROM ubuntu
ENTRYPOINT ["sleep"]
CMD ["5"]

this version uses a default time of 5, if not specified in command line
"docker run hello02" will sleep for 5
"docker run hello02 10" will sleep for 10

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