DevOps, Kubernetes, and Infrastructure Automation Zola 2026-06-20T00:00:00+00:00 https://esmaeele.github.io/tags/virtualization/atom.xml 2026-06-20T00:00:00+00:00 2026-06-20T00:00:00+00:00 EsmaeelE https://esmaeele.github.io/blog/vagrant/ <h1 id="run-multiple-debian-vms-with-vagrant-and-virtualbox">Run Multiple Debian VMs with Vagrant and VirtualBox</h1> <p>This guide sets up <strong>3 Debian virtual machines</strong> with working <code>vagrant ssh</code>, using <strong>VirtualBox</strong> as the provider. The box choice and shell provisioner below are what makes SSH work reliably on Debian — both trip people up if skipped.</p> <hr /> <h2 id="1-vagrantfile">1. Vagrantfile</h2> <p>Save this as <code>Vagrantfile</code> in your project directory. It defines the 3 VMs in a loop rather than repeating the same block three times:</p> <pre class="giallo" style="color: #CDD6F4; background-color: #1E1E2E;"><code data-lang="ruby"><span class="giallo-l"><span style="color: #F9E2AF;font-style: italic;">Vagrant</span><span style="color: #9399B2;">.</span><span style="color: #89B4FA;font-style: italic;">configure</span><span style="color: #9399B2;">(</span><span style="color: #A6E3A1;">&quot;2&quot;</span><span style="color: #9399B2;">)</span><span style="color: #CBA6F7;"> do</span><span style="color: #9399B2;"> |</span><span>config</span><span style="color: #9399B2;">|</span></span> <span class="giallo-l"><span style="color: #9399B2;font-style: italic;"> # Only this Debian box works reliably with Vagrant SSH + VirtualBox</span></span> <span class="giallo-l"><span> config</span><span style="color: #9399B2;">.</span><span style="color: #89B4FA;font-style: italic;">vm</span><span style="color: #9399B2;">.</span><span style="color: #89B4FA;font-style: italic;">box</span><span style="color: #94E2D5;"> =</span><span style="color: #A6E3A1;"> &quot;generic/debian12&quot;</span></span> <span class="giallo-l"></span> <span class="giallo-l"><span style="color: #9399B2;"> (</span><span style="color: #FAB387;">1</span><span style="color: #9399B2;">..</span><span style="color: #FAB387;">3</span><span style="color: #9399B2;">).</span><span style="color: #89B4FA;font-style: italic;">each</span><span style="color: #CBA6F7;"> do</span><span style="color: #9399B2;"> |</span><span>i</span><span style="color: #9399B2;">|</span></span> <span class="giallo-l"><span> config</span><span style="color: #9399B2;">.</span><span style="color: #89B4FA;font-style: italic;">vm</span><span style="color: #9399B2;">.</span><span style="color: #89B4FA;font-style: italic;">define</span><span style="color: #A6E3A1;"> &quot;debian</span><span style="color: #9399B2;">#{</span><span>i</span><span style="color: #9399B2;">}</span><span style="color: #A6E3A1;">&quot;</span><span style="color: #CBA6F7;"> do</span><span style="color: #9399B2;"> |</span><span>vm</span><span style="color: #9399B2;">|</span></span> <span class="giallo-l"><span> vm</span><span style="color: #9399B2;">.</span><span style="color: #89B4FA;font-style: italic;">vm</span><span style="color: #9399B2;">.</span><span style="color: #89B4FA;font-style: italic;">hostname</span><span style="color: #94E2D5;"> =</span><span style="color: #A6E3A1;"> &quot;debian</span><span style="color: #9399B2;">#{</span><span>i</span><span style="color: #9399B2;">}</span><span style="color: #A6E3A1;">&quot;</span></span> <span class="giallo-l"><span> vm</span><span style="color: #9399B2;">.</span><span style="color: #89B4FA;font-style: italic;">vm</span><span style="color: #9399B2;">.</span><span style="color: #89B4FA;font-style: italic;">network</span><span style="color: #A6E3A1;"> &quot;private_network&quot;</span><span style="color: #9399B2;">,</span><span style="color: #F38BA8;"> ip</span><span style="color: #9399B2;">:</span><span style="color: #A6E3A1;"> &quot;192.168.56.</span><span style="color: #9399B2;">#{</span><span style="color: #FAB387;">149</span><span style="color: #94E2D5;"> +</span><span> i</span><span style="color: #9399B2;">}</span><span style="color: #A6E3A1;">&quot;</span></span> <span class="giallo-l"></span> <span class="giallo-l"><span> vm</span><span style="color: #9399B2;">.</span><span style="color: #89B4FA;font-style: italic;">vm</span><span style="color: #9399B2;">.</span><span style="color: #89B4FA;font-style: italic;">provider</span><span style="color: #A6E3A1;"> &quot;virtualbox&quot;</span><span style="color: #CBA6F7;"> do</span><span style="color: #9399B2;"> |</span><span>vb</span><span style="color: #9399B2;">|</span></span> <span class="giallo-l"><span> vb</span><span style="color: #9399B2;">.</span><span style="color: #89B4FA;font-style: italic;">memory</span><span style="color: #94E2D5;"> =</span><span style="color: #FAB387;"> 1024</span></span> <span class="giallo-l"><span> vb</span><span style="color: #9399B2;">.</span><span style="color: #89B4FA;font-style: italic;">cpus</span><span style="color: #94E2D5;"> =</span><span style="color: #FAB387;"> 1</span></span> <span class="giallo-l"><span style="color: #CBA6F7;"> end</span></span> <span class="giallo-l"></span> <span class="giallo-l"><span style="color: #9399B2;font-style: italic;"> # Required to be able to SSH into the guest machines</span></span> <span class="giallo-l"><span> vm</span><span style="color: #9399B2;">.</span><span style="color: #89B4FA;font-style: italic;">vm</span><span style="color: #9399B2;">.</span><span style="color: #89B4FA;font-style: italic;">provision</span><span style="color: #A6E3A1;"> &quot;shell&quot;</span><span style="color: #9399B2;">,</span><span style="color: #F38BA8;"> inline</span><span style="color: #9399B2;">:</span><span style="color: #A6E3A1;"> &lt;&lt;-SHELL</span></span> <span class="giallo-l"><span style="color: #89B4FA;font-style: italic;"> chmod</span><span style="color: #FAB387;"> 700</span><span style="color: #A6E3A1;"> /home/vagrant/.ssh</span></span> <span class="giallo-l"><span style="color: #89B4FA;font-style: italic;"> chmod</span><span style="color: #FAB387;"> 600</span><span style="color: #A6E3A1;"> /home/vagrant/.ssh/authorized_keys</span></span> <span class="giallo-l"><span style="color: #89B4FA;font-style: italic;"> chown</span><span style="color: #A6E3A1;"> -R vagrant:vagrant /home/vagrant/.ssh</span></span> <span class="giallo-l"><span style="color: #A6E3A1;"> SHELL</span></span> <span class="giallo-l"><span style="color: #CBA6F7;"> end</span></span> <span class="giallo-l"><span style="color: #CBA6F7;"> end</span></span> <span class="giallo-l"><span style="color: #CBA6F7;">end</span></span></code></pre> <p>This produces <code>debian1</code>, <code>debian2</code>, <code>debian3</code> on <code>192.168.56.150</code>, <code>.151</code>, <code>.152</code> respectively — same result as writing out three separate blocks, less to maintain.</p> <hr /> <h2 id="2-usage">2. Usage</h2> <p><strong>Destroy any previous VMs and clear old state:</strong></p> <pre class="giallo" style="color: #CDD6F4; background-color: #1E1E2E;"><code data-lang="shellscript"><span class="giallo-l"><span style="color: #89B4FA;font-style: italic;">vagrant</span><span style="color: #A6E3A1;"> destroy -f</span></span> <span class="giallo-l"><span style="color: #89B4FA;font-style: italic;">rm</span><span style="color: #A6E3A1;"> -rf .vagrant</span></span></code></pre> <p><strong>Start all 3 VMs:</strong></p> <pre class="giallo" style="color: #CDD6F4; background-color: #1E1E2E;"><code data-lang="shellscript"><span class="giallo-l"><span style="color: #89B4FA;font-style: italic;">vagrant</span><span style="color: #A6E3A1;"> up</span></span></code></pre> <p><strong>SSH into each VM:</strong></p> <pre class="giallo" style="color: #CDD6F4; background-color: #1E1E2E;"><code data-lang="shellscript"><span class="giallo-l"><span style="color: #89B4FA;font-style: italic;">vagrant</span><span style="color: #A6E3A1;"> ssh debian1</span></span> <span class="giallo-l"><span style="color: #89B4FA;font-style: italic;">vagrant</span><span style="color: #A6E3A1;"> ssh debian2</span></span> <span class="giallo-l"><span style="color: #89B4FA;font-style: italic;">vagrant</span><span style="color: #A6E3A1;"> ssh debian3</span></span></code></pre> <p><strong>Stop all VMs:</strong></p> <pre class="giallo" style="color: #CDD6F4; background-color: #1E1E2E;"><code data-lang="shellscript"><span class="giallo-l"><span style="color: #89B4FA;font-style: italic;">vagrant</span><span style="color: #A6E3A1;"> halt</span></span></code></pre> <p><strong>Remove all VMs permanently:</strong></p> <pre class="giallo" style="color: #CDD6F4; background-color: #1E1E2E;"><code data-lang="shellscript"><span class="giallo-l"><span style="color: #89B4FA;font-style: italic;">vagrant</span><span style="color: #A6E3A1;"> destroy -f</span></span></code></pre> <hr /> <h2 id="3-notes">3. Notes</h2> <ul> <li>Use <strong><code>generic/debian12</code></strong> — other boxes (like <code>debian/bookworm64</code>) can leave <code>authorized_keys</code> empty and break SSH.</li> <li>The <strong>shell provisioner block</strong> is required on Debian to set correct SSH permissions; without it, <code>vagrant ssh</code> fails.</li> <li>Each VM uses a <strong>private network</strong> for predictable IPs.</li> <li>Tested with <strong>VirtualBox 7.x</strong> and the Vagrant AppImage on Linux, macOS, and Windows.</li> </ul>