debconf: unable to initialize frontend: Dialog
<p>I am building my own ubuntu VM with <a href="http://packer.io" rel="noreferrer">packer</a> to host on <a href="https://atlas.hashicorp.com/" rel="noreferrer">Atlas</a> and I'm using the <code>packer build template.json</code> to test if it will be a success if I was to use <code>packer push template.json</code> I am getting this error when the I run the <a href="https://github.com/fideloper/Vaprobash/blob/master/scripts/mysql.sh" rel="noreferrer">mysql.sh</a> script.</p>

<pre><code>virtualbox-iso: debconf: unable to initialize frontend: Dialog
    virtualbox-iso: debconf: (Dialog frontend will not work on a dumb terminal, an emacs shell buffer, or without a controlling terminal.)
    virtualbox-iso: debconf: falling back to frontend: Readline
    virtualbox-iso: Configuring mysql-server-5.6
    virtualbox-iso: ----------------------------
    virtualbox-iso:
    virtualbox-iso: While not mandatory, it is highly recommended that you set a password for the
    virtualbox-iso: MySQL administrative "root" user.
    virtualbox-iso:
    virtualbox-iso: If this field is left blank, the password will not be changed.
    virtualbox-iso:
</code></pre>

<p>What is it that I'm missing with <code>debconf:</code></p>

<p>Thanks.</p>