title: Dockerfile is building from Centos:7 - is there a way to instruct npm to be installed?
body: <p>I have to make use of an existing Dockerfile, which generates a docker image from Centos 7.  (FROM centos:7  , is the first line in the Dockerfile.)</p>
  
  <p>I need to be able to run 'npm install' and 'npm run' commands within the containers that will be running this image, but npm is not installed.  The ways I find online how to install npm on Centos 7 also do not work, as they rely on things such as apt-get which also is not installed in the container.  Not having sudo also seems to be an issue.</p>
  
  <p><strong>Is there a way to configure the actual Dockerfile, to build the image, and have npm installed on that image being built?  If not - how can I go about installing npm within the docker containers that will run this Centos7 image?</strong></p>
  
  <p>ANSWER:  I added this to the Dockerfile:</p>
  
  <pre><code>RUN yum install -y epel-release
  RUN yum install -y npm nodejs
  </code></pre>