title: how to reference variable variable in jinja2 template
body: <p>In one of my ansible roles I would like to set up a basic network/interfaces stanza, like this:</p>
  
  <pre><code>auto eth1
  ifaces eth1 inet dhcp
      dns-nameserver {{ ansible_eth1.ipv4.address }}
      dns-search maas
  </code></pre>
  
  <p>I have variables, and I create the stanza with the jinja2 template:</p>
  
  <pre><code>auto {{ iface }}
  ifaces {{ iface}} inet dhcp
      dns-nameserver {{ ansible_{{ iface }}.ipv4.address }}
      dns-search maas
  </code></pre>
  
  <p>Can I reference a variable variable in a template?  I also tried creating a variable in the ansible yaml, like nserver: ansible_{{iface}}.ipv4.address, that didn't work either!</p>