title: Why am I getting Unable to correct problems, you have held broken packages
body: <p>Trying to run Dockerfile and it fails at installing npm.</p>
  
  <p>ERROR:</p>
  
  <pre><code>Unable to correct problems, you have held broken packages.
  The command '/bin/sh -c apt-get install -y npm' returned a non-zero code: 100
  </code></pre>
  
  <p>Dockerfile:</p>
  
  <pre><code>FROM ubuntu:14.04
  
  MAINTAINER Giacomo Vacca "giacomo.vacca@gmail.com"
  
  ENV REFRESHED_AT 2015-01-19
  ENV DEBIAN_FRONTEND noninteractive
  
  RUN apt-get autoremove
  RUN npm -v
  
  RUN apt-get update
  RUN apt-get upgrade -y
  
  RUN apt-get install --yes curl
  RUN curl --silent --location http://deb.nodesource.com/setup_0.10 | sudo bash -
  RUN apt-get install -y nodejs
  RUN apt-get install --yes build-essential
  
  RUN rm /usr/bin/node
  
  # needs this to find the nodejs exec
  RUN ln -s /usr/bin/nodejs /usr/bin/node
  
  RUN apt-get install -y npm  &lt;--- FAIL
  RUN /usr/bin/npm install socket.io@0.9.14
  
  EXPOSE 8080
  
  ENTRYPOINT ["/usr/bin/node", "/root/server.js"]
  </code></pre>