Identical dockerfiles giving different behaviours

Question

I am using the following dockerfile taken from (http://txt.fliglio.com/2013/11/creating-a-mysql-docker-container/):

FROM ubuntu

RUN dpkg-divert --local --rename --add /sbin/initctl

RUN ln -s /bin/true /sbin/initctl

RUN echo "deb http://archive.ubuntu.com/ubuntu precise main universe" > /etc/apt/sources.list

RUN apt-get update

RUN apt-get upgrade -y

RUN apt-get -y install mysql-client mysql-server

RUN sed -i -e"s/^bind-address\s*=\s*127.0.0.1/bind-address = 0.0.0.0/" /etc/mysql/my.cnf

ADD ./startup.sh /opt/startup.sh

EXPOSE 3305

CMD ["/bin/bash", "/opt/startup.sh"]

This works with no errors when I build on Docker version 0.8 on my local machine.

I have been experimenting with trusted builds: https://index.docker.io/u/hardingnj/sqlcontainer/

however on the docker servers I get an error with the second RUN command:

[91mln: failed to create symbolic link `/sbin/initctl': File exists

[0m

Error: build: The command [/bin/sh -c ln -s /bin/true /sbin/initctl] returned a non-zero code: 1

I was under the impression that Dockerfiles should work identically independently of context? Perhaps the versions of ubuntu that I am pulling aren't identical?

Andy Andy · Accepted Answer · 2014-02-18T17:34:29

It is possible that the versions of the ubuntu image are different. To be extremely precise you could give the full image id that you want in the FROM statement, e.g.

# This is the id of the current Ubuntu 13.10 image.
# The tag could move to a different image at a later time.
FROM 9f676bd305a43a931a8d98b13e5840ffbebcd908370765373315926024c7c35e
RUN dpkg-divert --local --rename --add /sbin/initctl
...

Identical dockerfiles giving different behaviours

1 Answers