title: Docker: cannot install openssh-server
body: <p>I build the Docker based on Ubuntu 16 and want to allow PuTTY access to the Ubuntu.
  I have added the line to the docker file:</p>
  
  <pre><code>#Download base image ubuntu 16.04
  FROM ubuntu:16.04
  
  # Update Software repository
  RUN apt-get update
  
  # Install nginx, php-fpm and supervisord from ubuntu repository
  RUN apt-get install -y nginx php7.0-fpm supervisor &amp;&amp; \
      rm -rf /var/lib/apt/lists/*
  
  RUN apt-get autoclean  -y supervisor
  RUN apt-get install openssh-server -y supervisor
  </code></pre>
  
  <p>But when I build the image it gives me</p>
  
  <blockquote>
    <p>Step 5/18 : RUN apt-get install openssh-server -y supervisor  --->
    Running in c9425deece29 Reading package lists... Building dependency
    tree... Reading state information... E: Unable to locate package
    openssh-server</p>
  </blockquote>
  
  <p>How to fix it? My task is: to allow connection from a host (Windows) to the docker container via PuTTY.</p>