Why golden images

There are ~15 VMs in this lab. Not one of them was installed from an ISO by hand. Every single one is a clone of a single golden image — one carefully prepared template — customised at first boot by cloud-init.

The alternative (install Ubuntu by hand, fifteen times) is slow, and worse, it's inconsistent: little differences creep in between boxes and become the bugs you can't reproduce. A golden image makes every VM start from the exact same known-good baseline.

one template (VM 9999)  --clone-->  VM 107  (becomes K8s-Master)
                        --clone-->  VM 112  (becomes K8s-NFS)
                        --clone-->  ...      every VM in the lab

Why we use this: consistency and speed. Every VM is identical at birth, so "it works on that box but not this one" stops being a mystery. And spinning up a new, fully-configured VM goes from a 30-minute install to a 30-second clone. This is the same idea as a base container image — build once, stamp out many.