title: Docker base image for perl; E: Package 'libssl1.0.0' has no installation candidate
body: <p>I have a dockerfile that uses perl:5.22 as the base image
  When I do:</p>
  
  <pre><code>#Dockerfile:
  
  From perl:5.22
  RUN apt-get update &amp;&amp; apt-get install libssl1.0.0 libssl-dev
  </code></pre>
  
  <p>I get this error:
  When I do: <code>sudo apt-cache policy libssl1.0.0</code> in the dockerfile, like this:</p>
  
  <pre><code>#Dockerfile:
  
  From perl:5.22
  RUN apt-cache policy libssl1.0.0 &amp;&amp; \
      apt-cache policy libssl-dev
  RUN apt-get update &amp;&amp; apt-get install libssl1.0.0
  </code></pre>
  
  <p>I get:</p>
  
  <blockquote>
    <p>Step 2/3 : RUN apt-cache policy libssl1.0.0 &amp;&amp;     apt-cache policy
    libssl-dev  ---> Running in a60f0185ef5a libssl1.0.0:<br>
    Installed: (none)
    Candidate: (none)<br>
    Version table: 
    libssl-dev:<br>
    Installed: 1.1.0f-3+deb9u2<br>
    Candidate: 1.1.0f-3+deb9u2<br>
    Version table:<br>
    *** 1.1.0f-3+deb9u2 500
            500 <a href="http://security.debian.org/debian-security" rel="nofollow noreferrer">http://security.debian.org/debian-security</a> stretch/updates/main amd64 Packages
            100 /var/lib/dpkg/status
         1.1.0f-3+deb9u1 500
            500 <a href="http://deb.debian.org/debian" rel="nofollow noreferrer">http://deb.debian.org/debian</a> stretch/main amd64 Packages</p>
  </blockquote>
  
  <p>There's no available candidate to install <strong><em><code>libssl1.0.0</code></em></strong>; I get: </p>
  
  <blockquote>
    <p>E: Package 'libssl1.0.0' has no installation candidate</p>
  </blockquote>
  
  <p>However there's a candidate to install the <strong><em><code>libssl-dev</code></em></strong> package, but none for the <strong><em><code>libssl1.0.0</code></em></strong></p>
  
  <p>I'm new with docker; <strong><em>does <a href="https://github.com/perl/docker-perl/blob/1c201e950ebe90f35c449f69df6ca7151cb0068d/5.022.004-64bit/Dockerfile" rel="nofollow noreferrer">the perl 5.22 base image</a> already come with libssl1.0.0 already preinstalled in the image?</em></strong> I couldn't see it in their base image and secondly, <strong>*how do I install this package <em></strong><code>(libssl1.0.0)</code><strong></em> in my dockerfile if there's no candidate available to install it*</strong>?</p>
  
  <p>Lastly, since the base image already comes preinstalled with the libssl-dev could I use this package, <strong><em><code>libssl-dev</code></em></strong>, instead of the libssl1.0.0, <strong><em>is there a difference between <code>libssl-dev</code> and <code>libssl1.0.0</code></em></strong> ?</p>